For his original universe version see Heinrich
Otherwise known as the Angel Killer, the Armoured Berserker is a feral humanoid with seemingly no intelligence whatsoever and limitless hate for angels.
The Fairies and Elves continuously mention a "scary monster" patrolling the woods, but he doesn't attack anyone. Luka suspects they're just prejudiced and that he just has a scary appearance but is relatively friendly. He is sadly mistaken.
It's not a few moments after Luka acquires Sylph before he starts feeling a tingling sensation. Ilias comments that it seems like holy magic which went "berserk and degenerated" and the Armoured Berserker promptly materialises behind them. His whole vocabulary appears to consist of ANGEL. Luka is confused why he is attacking them, but Ilias explains that he is attacking in reaction to their Holy energy.
The fight ensues but Luka and his party are easily beaten by the Berserker. He is about to deliver the final blow to Luka when Nero materialises in front of the Berserker and blocks the attack with his scythe. Neris takes the unconscious Luka and his companions back to the Pocket Castle and leaves Nero to deal with the Armoured Berserker alone. Which Nero does, effortlessly. Before turning into particles, the Berserker screams "WWWOOOOOoooo", likely shocked by how powerful Nero is. Nero notes that he wasn't destroyed and that so long as his soul remains, he will go berserk again and again.
If Luka and the others manage to defeat the Berserker, Nero and Neris do not intervene and the party remains in the forest, rather than being transported to the castle. Luka still acquires access to the angel race in this scenario. The Berserker's defeat also leaves Alice or Ilias visibly confused, considering the large difference in power that should be between him and the party at this point.
Not much is known about the Berserker at this point. Other than the fact he is almost certainly a Heinrich, who was not locked away in the Sealed Sinners Prison and now roams the world killing any Angel he sees. However, we did see an image of Black Alice and the Armored Berserker in the trailer, not fighting but standing next to each other. So it is possible he also serves Black Alice (or maybe Black Alice and Heinrich are together after all? (see 2:21-2:23 of the Paradox trailer)).
- Red Lotus Flame Dance-Physical Attack, Random Enemy, Attack 4 Times, Fire Attribute, Burn 10%
- シャドウメサイア (Shadow Messiah)-Certain Hit, All Enemies, Dark Attribute
- 天塵剣 (Heavenly Dust Sword)-Physical Attack, One Enemy, Angel Attribute
- エンジェルダスト (Angel Dust)-Certain Hit, All Enemies, Angel Attribute
Well, you aren't supposed to beat him. Simple as that. But that doesn't mean it's impossible. Just try to level up Luka and your primary party members to 30 before encountering him. NG+ can help you with this. I can't provide a unique strategy for him as I'm yet to beat him myself, despite him being easier than Sphinx. Just fight him like you would one of the super bosses and don't use the Sonic or Bio elements. Anything else is fine.
- The Armoured Berserker is Heinrich in a world where he didn't turn into pure, holy energy and instead took a physical form of Angel Halo.
- Angel Attribute hits angels stronger.