Defeating the Fire Dragon
Stay out of the Fire Dragon's range. It has a range of three spaces, the same as a longbow. Hopefully you had the foresight to transform your other lords into their respective second class character. (Lyn - Blade Lord and Hector - Great Lord). Lyn's Sol Katti, given to her by Athos, was fashioned for dealing with Wyverns; therefore, it can actually deal some damage to the dragon. If you happen to have Thor's Ire (Nils can use it to raise critical levels), then use it on Lyn. Her critical percentage will be raised and you might get lucky enough to see an incredible show. All of this relies on the fact that you can keep her alive -- HP in the 40's is best). Keep Eliwood a few paces away from Lyn in order to rescue her once she has completed her attack on the dragon. The Elixirs you have will be useful for keeping her alive. Also, a Druid/Sage/Bishop with Heal/Mend can also aid you. Keep attacking/rescuing/healing with Lyn until the dragon dies. This may take some time, but it keeps your company alive. Also, if Lyn is not a Blade Lord, try using Hector's Armads, if he is a Great Lord; do not use Eliwood -- the Durandal may seem like a good idea but for some reason the dragon can attack twice if you use it. Also, you will need him or Marcus to rescue the attacker.
The last Boss of the game is obviously a dragon. By the time you reach him, you should have Athos The Archsage. If you are in the Eliwood path, you should have obtained some Elixirs in the chapter with the cave of lava, in which you need to defeat the guardians to get to the Durandal. Equip Athos with Aureola (the light spell that he has). This does a good 20 points of damage on the dragon. The dragon has a maximum of 120 HP. Get into range of the dragon, end your phase, and let the dragon attack. On your turn, use an Elixir on him for healing. Get the dragon down to 40 HP, and on your turn attack with Athos, Lyn, Hector, and Eliwood to finish it.
Have your three strongest characters (Hawkeye, Marcus, and your third strongest) and rescue your lords, just to be safe. Make sure that if you attack the dragon, you will still have someone to heal the attacker. Position Athos directly in front of it and attack with his light spell Aureola. If you still have Pent/Serra/Priscilla, have anyone positioned directly behind Athos for healing. The dragon might do 37 damage to Athos, so Mend might not give him full health. After you attack first, heal Athos immediately. The only time you should attack is on counter-attacks. Otherwise, you will have no time to heal, and Athos will die.
Make sure Hector is a level 20 Great Lord, and his HP is maxed out. Attack with Armads and you will do a good deal of damage. Lyn as a level 20 Blade Lord with Sol Katti or Athos will also work, However, but Hector is the best. It will take about five hits (if you do not get a critical hit) to defeat the Fire Dragon with only Hector. Also try to have support characters near him so that he gets a power bonus. Do not attack with Eliwood; for some reason the dragon can attack twice, which is a bad thing.
The best character to fight the Dragon in the Final Chapter is Athos. However, his best spell is not Aureola. Although it does 20 damage to it, he has a better spell. His best spell is Luna. When you get Luna, save it for him. He can do 30 damage a turn to the Dragon, as opposed to 20.
Equip Athos with the dark magic book Luna, which negates Resistance. He will do 30 damage to the Dragon. On your first turn, have Nils use the amulet that can raise allies critical hit %, and attack the Fire Dragon with Athos. He should get a critical hit if done correctly. This will do 30 x3 damage to the Dragon, or 90 of its 120 HP. Heal or rescue Athos with a horseback unit such as Eliwood's second class, then attack on your next turn. This will deal the remaining 30 damage, defeating the final Boss in two hits.
Have Athos and any healer. Make sure Athos is at full health then move him within range to attack the dragon, but do not attack it. Make sure no one else is in range of the dragon's attack, then end your turn. On the enemies turn, the dragon will attack Athos, but will not kill him. Then, simply move Athos out of range and heal him. When he is at full health, just do it again.
In Chapter 19, you can get Luna magic from a chest in the northwest corner. Save it. In the final chapter, give it to Athos and you can do 60 damage to Nergal in one turn. Hit him after he attacks you, then on your turn, any strong character can defeat him. If you still have Luna, use it on the dragon to do 30 damage.
Have Canas or Athos use Eclipse on the dragon (with as high skill as possible), which can do 60 damage. If you miss, have Nils give him a second chance. When done, attack with Durandal, Sol Katti, and Armads, but be careful of Eliwood; the Durandal is heavy and the dragon might attack twice. Then, have Athos, Pricsilla, Serra, Pent, or Renault use Fortify if the dragon is not dead. Continue hitting with legendary items and Eclipse until he is defeated.
Chapter 16
This trick requires need Marcus (most needed), Oswin, and Princsellia. First, have Marcus rescue Princsellia. Have Oswin and your lords (except for your best one) go straight ahead. Once Marcus reaches the gate to Raven, drop Princsellia. Because she cannot move all the way to Raven, have her move four steps. Once she reaches Raven, select "Talk" and he will join you. Have Raven talk to Lucuis and she will join. Have Raven, Lucuis, and your best lord defeat the enemy reinforcements. Before you go to the Boss, you will see a square with a knight and two chests. Crack the wall and kill the knight. He will give you a chest key that can be used five times. Open the left chest for a Knights Crest. Give the crest to Oswin and make him use it. The other chest contains a silver sword. For the Boss, have Marcus attack with the hammer and Oswin attack one space away with the javelin.
Chapter 16x
In order to unlock the side quest after Chapter16, you need to keep one of the green soldiers alive. To do this, have one of your horse riders rescue one of them, and do not let go.
Go towards the top and you will have to defeat a few people. Send somebody (Marcus recommended) over to Fargus, but stay very close to the top or the really tough pirates will come after you.
This chapter is probably the easiest in the game when done correctly. When setting your formation, place Marcus as far up as you can and Dorcas in the bottom left. When you start, send Dorcas to the house with the red roof closest to the left, to get the Devil Axe. Next, send someone to the red house beside the inn to get Canas. Send Marcus ahead up, around, and along the wall with about four of Fargus' pirates. Then, send the rest of your fleet at the end of the wall. Fargus tells his men to attack you. Then, get Marcus to talk to Fargus.
Chapter 22
For a sure win on Chapter 22 (in which you protect Nils), you need a long bow with either Rebecca or Will. You need also Marcus with 2 Light Runes if possible, Oswin preferably as a general, Erk Best as a Sage, someone with a javelin or hand axe, and all the other units allowed. Leave the Ostia units at the bottom of the stairs followed by two (two by two) Paladins, then Erk and the person with a javelin or hand axe. For the second long bow, get Rath (the green nomad). Deploy Merlinus and in that small area where Nils is put, the rest of your units for substitutes while you heal the six needed units.
Side quests
There are certain things you must do in order to unlock all the side quests. Some Chapters can be different; it all depends on what you have done.
Chapter 7x: Complete Chapter 7 in less than 15 turns.
Chapter 13x: Visit the northwestern village on Chapter 13.
Chapter 16x: Keep one green soldier alive in Chapter 16.
Chapter 18x: Finish Chapter 18 in less than 16 turns.
Chapter 22x: Recruit Hawkeye in Chapter 22 and have him gain 700 experience points.
Chapter 23a: Lord's level sums equal 49 or less.
Chapter 23b: Lord's levels are 50 or more (Chapter 23b will allow you to recruit a new character).
Chapter 25a: Level of units upgradeable via Guiding Ring/Hero Crest.
Chapter 25b: Level of units upgradeable via Hero Crest/ Guiding Ring.
Chapter 26x: Recruit Jaffar in Chapter 26 and have him live.
Access secret shop
On the "Protect Nils" mission, you can access one of the secret shops if you stole the Members Card on the top left. Have a thief with the Members Card walk to the right of the pillar, then select the secret option to gain access. You can buy Elfire Physic and other great items.
Get to secret shops
You must steal the Member Card in the chapter with Darin as the Boss. Have some of your units to go right, including Matthew. At the staircase by the crack in the wall, a thief will appear. You can steal the Member Card from him.
Karla: After you complete the game, you can unlock Hector Mode. In Hector Mode you can get Karla to join you. Karla is the probably one of the most difficult characters to obtain in the game. In the side quest where your mission objective is to purchase supplies, you will need a Warrior Bartre at level 5 or higher. On the first turn, she will come out and attack. Equip Bartre with a bow so that he does not accidentally kill her. After that, and if Bartre survived, talk to her so she will join. She has a Wo Dao, which has a very high critical rate, so Bartre must be able to survive. He only needs to survive one assault so that you can talk to her. You only have five turns to get supplies and get Karla, so must be quick.
Extra characters
Your enemy works for a house or organization. It will say the name of the characters or the group they are working for. if it shows a face instead of a symbol you can almost always get that unit with green units.
Note: Your character cannot be upgraded unless they are at level 10 or higher.
Archer to Sniper: Orion's Bolt/Earth Seal
Nomad to Nomadic Trooper: Orion's Bolt/Earth Seal
Knight to General: Knight's Crest/Earth Seal
Calavier to Paladin: .Knight's Crest/Earth Seal
Wyvern Rider to Wyvern Lord: Elysian Whip/Earth Seal
Peg. Knight to Falco Knight: Elysian Whip/Earth Seal
Pirate to Berserker: Conquer's Emblem
Troubeder to Valkrie: .Guilding Ring/Earth Seal
Mage to Sage: .Guilding Ring/Earth Seal
Monk or Cleric to Bishop: .Guilding Ring/Earth Seal
Shaman to Druid: Guilding Ring/Earth Seal
Mercenary to Hero: Hero's Seal/Earth Seal
Myrmidon to Sword Master: Hero's Seal/Earth Seal
Fighter to Warrior: .Hero's Seal/Earth Seal
Eliwood to Knight Lord: Upgraded by Athos
Lyn to Blade Lord: Heaven's Seal
Hector to Great Lord: Heaven's Seal
Theif to Assaian: Fell Contract
Bard or Dancer: Cannot be upgraded
Archsage: Cannot be upgraded
Eliwood
Eliwood is the second Lord that you get. He has a Rapier (which is good on Infantry) which only can be used by him. The Rapier also goes out quick; it is recommended that he also be given another sword. When you first get Eliwood, he seems like he is not the best fighter. Train him, because he will become very good. If you would like him to be strong, get him to level 18 to 20 by the end of Chapter 27. Eliwood, when he gets transformed, will be a Knight Lord and he will be on a horse and be able to use lances. Lyn, will become a Blade Lord, and be able to use bows.
Legault: Become an assassin
In the Dread Isle, a thief named Legault appears and wants to steal things. Take Lyn and talk to him whenever you get the chance. After you finish the chapter, advance until Battle Before Dawn (Jaffar and Nino). Talk to Nino with Lyn or Eliwood and take Nino and talk to Jaffar. After you win, accept the side quest and you will fight Sonia, who is holding something called a Fell Contract. Defeat Sonia, get the Fell Contract, then have Legault use it to become an assassin.
Lucius: Strong magic wielder
When you first get him, is terrible. Be patient and train him hard in Lyn's story. Have him at least at level 8 when you begin Eliwood's story. If you do this and use him every chapter, he can turn into your best magic wielder; perhaps even better than Pent if you use him enough. This also can be done with other people that are terrible when you first get them, including Florina.
Lyn
Lyn is the first lord you receive. She eventually gets the Mani Kati, a sword which only she can wield. It is a smart idea to train her because later in the game you will get what is called Heaven Seals, for Lords over level 10 that are deemed worthy (Lyn first, Hector second, and Athos the Archsage automatically transforms Eliwood). Lyn will be one of your good fighters because she gets to level 6 before you get more than three people. When you start Eliwood's campaign, you will get Lyn again. Give her a steel sword with the Mani Kati, as it goes out quick.
Nils: Get to level 7 or higher in Lyn's Story
Kill everyone except the Boss in a chapter, then have someone wait each turn. Have Nils play for them and end the turn. Note: This only works on chapters that require Boss kills or seize the thrones.
Easy support
At the end of chapters such as 13, 18x, or any other where at the end you only need to seize a gate or kill the last enemy, put everyone close to each other. Then, in every player phase, choose unit under the "A options". Choose page 6, "Support Chance". If any of your units can support another unit, it will be shown there.
Earth Crest
In the mission just before you can get Neo and Jaffar, where Wallace shows up, in the first village an old man will talk with you. When you are finished, he will give you an Earth Crest. This crest will allow you to upgrade any character higher than level 10. It is useful, but it is recommended that you go in with an a strong flyer such as Heath the wyvren rider. You must contend with an archer that has a silver bow. In the other village, you will get a Silence Staff to help you fight the Queen Of The 4 Fangs.
Ocean Seal
In the mission where you get Hawkeye, you can obtain a very unique item found nowhere else in the game called an Ocean Seal, which can be used to upgrade pirates, (DART) making them a Berserker like Hawkeye. The item is buried in the sand at the last row of spaces near Hawkeye's entrance. Get a Thief to stand on top of the right space to get it.
Quick Paladin
In Lyn's story in hard mode, you can get a Paladin. Because you do not have to class-up Wallace, train either Sain or Kent until they are level 20. The easiest way to do this is to take your time on Lundgren. Make sure he does not die until you reach those levels -- let him heal for a few turns in between attacks. When your Cavalier reaches level 20, use the Knight's Crest on him. Then when you go into Eliwood's or Hector's story and meet up with Lyn, you will have a Paladin who is much better than Marcus.