World of Blazing (烈火の世界, Rekka no Sekai lit. World of Raging Fire) is the seventh chapter of Book I of Fire Emblem Heroes.
The names of the five parts of this chapter are Blazing Trial (烈火の試練, Rekka no Shiren lit. Trial of Raging Fire), Two Noblemen (公子二人, Kōshi Futari lit. Two Princes), Baffling Labyrinth (迷宮に惑う, Meikyū ni Madou lit. The Labyrinth is Confusing), The Guardian (守護者は揺らがず, Shugosha wa Yuragazu lit. The Protector is Shaking), and Blazing Noblemen (烈火の公子, Rekka no Kōshi lit. Prince of Raging Fire).
Part 1: Blazing Trial
Subjective: The following part of this article is based upon the editor's personal experiences and opinions, and therefore may not be applicable for all readers.
Serra is protected by Matthew and an Emblian Thief, while the other Emblian Thief is on the bottom left on the map. To get the Thiefs' attention, send your own Thief unit, your Archer unit, or your Tome unit to their attack range.
When your turn begins, and if Matthew or any of those enemy Thieves survive, finish them off with your Sword unit, Axe unit, or Lance unit, as the Thieves can't attack straight.
Also, make sure you defeat Serra, otherwise she will heal her team during the Enemy Phase.
Part 2: Two Noblemen
Eliwood and an Emblian Green Cavalier are on the bottom left on this map, while Hector and an Emblian Lance Knight are on the top left. Unless you have your Pegasus Knight or a Wyvern Rider, your units can't get through the mountain blocks, and your Mounted units can't get through the tree blocks.
To gain the advantage, send your powerful Sword unit or your Red Tome unit to Hector's attack range, then counter in order to defeat him. Also, be aware that an enemy Lance Knight will get to your units, so if you can, send your Green Tome unit and defeat him.
Keep in mind that Eliwood and a Green Cavalier will get closer to your team. The best strategy is to send your Lance unit to defeat Eliwood, and then send your Sword unit to defeat that enemy Green Cavalier.
Part 3: Baffling Labyrinth
This whole map is a maze, and your team is on the top right of this map. There are breakable walls in this labyrinth. Send your units with an attack range and your melee unit to break that wall where you will go to Nino's attack range. If your unit who broke the wall is a Red Tome unit, send that unit to Nino's attack range and defeat her.
But be warned, even though Nino and an Emblian Blue Mage can't break the walls, Raven, an Emblian Sword Fighter and an Emblian Lance Knight can. Raven will break the wall on the bottom right to free that enemy Blue Mage, while that enemy Sword Fighter will break those walls on the bottom left and the middle left to free Nino.
Once you dealt with Nino and that enemy Lance Knight (if possible), send your Lance unit to defeat that enemy Sword Unit, then send your Green Tome unit to defeat that enemy Blue Mage, and finally, send your Sword unit or your Red Tome unit to defeat Raven.
Part 4: The Guardian
Send your Red Tome unit or your Archer unit or your Thief unit to an Emblian Green Mage's attack range behind the mountain blocks so you can counter and defeat him. However, that will the the attention from Lyn, Florina, and Hawkeye.
When Florina flies closer to your team, take her down with your Green Tome unit or your Archer unit (as it is effective against flying units). Then, send your powerful Lance unit to defeat Lyn, and then send your powerful Sword unit to defeat Hawkeye. Remember the Weapon Triangle and it should be easy to clear the stage.
Part 5: Blazing Noblemen
You will have 4 units on your team. You will also have 4 opponents and one boss: Eliwood, Hector, Lyn, an Emblian Bow Fighter, and an Emblian Lance Knight.
This is a tricky stage, so the best strategy is to send your Sword unit to Hector's attack range. Then send your Lance unit to Eliwood's attack range. Also, you can send your Green Tome unit in order to defeat that Emblian Lance Knight at ease.
But be careful, that will get Lyn's attention and she will get closer to your Green Tome unit. Send your Green Tome unit as far away as possible, and then send your powerful Lance unit to defeat Lyn.
Also, the Bow Fighter will get closer to your team as well, or he can attack your unit when your unit is in that enemy Archer's attack range. Defeat that enemy Archer as soon as possible.