Heroes Invade (英雄侵攻, Eiyū Shinkō lit. Invasion of Heroes) is the ninth chapter of Book I of Fire Emblem Heroes.
The names of the five parts of this chapter are Loyalty and Ambition (野望と忠義, Yabō to Chūgi), Noblity and Vanity (王道と邪道, Ōdō to Jadō lit. The Way of Evil and the Way of Kings, The Blue Crow (蒼鴉は見つめる, Sōa ha Mitsumeru lit. The Blue Crow is Staring), The Unknown (難攻不落, Nakōfuraku lit. Impregnable) and Princess of Death (死の皇女, Shi no Ōjo).
Part 1: Loyalty and Ambition
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.
There is a breakable wall next to your third unit, destroy it so that your other units can pass. But once your first Player Phase ends, the Enemy Phase begins and the enemy team will move to their positions.
When Michalis is close enough, send your powerful Sword unit or your Red Dragon unit to his attack range, counter, and take him down. You can also defeat him with your archer unit, as long as your archer unit is one square away from his attach range.
But beware, Camus, an Emblian Lance Flier, and an Emblian Red Cavalier will move together, and that Emblian Red Cavalier will protect Camus. Send your powerful Blue Tome unit to the enemy's attack range and get him out of your way. Then, defeat that Emblian Lance Flier with your Axe unit or your Archer unit. And finally, defeat Camus with your powerful Axe unit or your Green Tome unit.
Part 2: Nobility and Vanity
Zephiel is in his position between an Emblian Axe Knight and an Emblian Lance Knight, with an Emblian Cleric behind him. While Narcian is in the bottom left side of the map so that none of your ground units can get to him, unless you have your Sword Flier unit, and then you can defeat Narcian.
This is one of the difficult chapters yet, so make sure your team has enough power to defeat the three enemy knights. Also, remember the Weapon Triangle and defeat Zephiel with your powerful Lance/Blue Tome/Blue Dragon unit, then defeat that enemy Axe Knight with your powerful Sword/Red Tome/Red Dragon unit, and finally defeat that enemy Lance Knight with your powerful Axe/Green Tome/Green Dragon unit.
Keep in mind that you also need to take out that Emblian Cleric, otherwise she will heal the enemies.
Part 3: The Blue Crow
You will have 4 units on your team. You will also have 5 opponents: Ursula, an Emblian Sword Cavalier, an Emblian Axe Knight, an Emblian Lance Knight, and an Emblian Green Cavalier.
The two Emblian Knights can move slowly, but Ursula and the two Emblian Cavaliers can easily pass through, even breaking the walls. Fortunately, the enemy Cavaliers can't get through the trees on the map.
However, when they are close enough, make sure you remember the Weapon Triangles and defeat Ursula with your powerful Green Tome unit or your Axe unit, then defeat that Sword Cavalier with your powerful Blue Tome unit or your Lance unit, and finally defeat that Green Cavalier with your powerful Red Tome unit or your Sword unit.
Also, defeat the enemy Lance Knight on the left with your Green Tome unit and defeat the enemy Axe Knight with your Red Tome unit.
Part 4: The Unknown
You will have 4 units on your team. You will also have 4 opponents and one boss: Bruno, an Emblian Bow Cavalier, an Emblian Axe Knight, and 2 Emblian Clerics.
Bruno is expecting your team to get to him, as well as the Emblian Bow Cavalier, because they're both protected by the unbreakable walls. Send your powerful Archer unit to the enemy Bow Cavalier's attack range. Then, send your powerful Green Tome unit to the Bruno's attack range. Make sure that both of your units are powerful enough to defeat those enemies, and if they are not defeated, 2 Emblian Clerics will heal them both respectfully. And watch out for the Bruno's Critical Skill "Growing Thunder", which will allow him to attack first even during your Player Phase.
Also, the Emblian Axe Knight will move one square at a time, so defeat that unit with your powerful Red Tome unit.
And make sure you defeat both Clerics as soon as possible.
Part 5: Princess of Death
In this battle, as soon as your first turn ends, the Emblian Troubadour will raise the stats to both Princess Veronica and Xander, and then they will move to any kind of position in order to trick you, so look out for that.
Remember the Weapon Triangle and send your powerful Green Tome unit to the enemy Blue Mage's attack range so you can counter and defeat him. But be warned, the enemy Sword Fighter will have the advantage as soon as he gets closer to your team. If you have a powerful Lance unit, keep your Green unit behind and defeat that enemy with your Lance unit.
When Xander is close enough, take him down with your powerful Lance/Blue Tome/Blue Dragon unit. Also, be aware that the enemy Cleric can heal the enemy at any time, so take her down as soon as possible.
Finally, Veronica will step in and battle. However, you really need to be more careful of her Critical Skill "Reprisal", as she can increase her attack power in order to defeat your units. And don't forget about her other effects, because as soon as she ends her attack, she will damage your other units and she will give them penalties. Defeat Princess Veronica with all the power you have with your Red units and you clear this stage.