- Name: Berserk (Belselk in the Original English Language Wild Arms)
- Age: Unknown (Over 1000 years old)
- Height: Unknown
- Weight: Unknown
- Race: Metal Demon, Night Crawler
- Birthplace: Saturn Hiades
- Weapon: Disrupt Hammer
Known as Belselk in the original Wild Arms, Berserk is the classic example of the power muscle you would see in other games. He found pleasure in destruction, and was the one behind Adlehyde's total destruction following the Ruin festival. He successfully abducted Lolithia, Barbados, and Diablo from the festival, enlisting the help of other demons. His main objective in destroying Adlehyde was to steal Cecilia's tear drop, which she gives willingly. Following this, he is challenged by Jack, and loses. He calls off his attack following the battle.
We next see him in several cutscenes involving the cocoon of Mother. He succeeds in destroying one of the statues that keep Mother's heart bound, and keeping her sealed. He siks Orga Widow on the team in an effort to distract them, but fails in this respect, also. (In Alter Code: F, he battles them himself.) He is present when Mother is reborn, and witnesses her proclamation to destroy Filgaia. While her message floors Zeikfried, it has little effect on Berserk, who delights in destruction and pain.
Following the Mt. Zenom failure, he begins to quickly lose favour in the Photosphere. Zeikfried and the other Quarter Knights reprimand him (especially Lady Harken, who offers to destroy the trio herself), and Berserk swears revenge on the trio for his embarrassments.
Floating the rumour of treasure at the Volcannon Trap to others, including Calamity Jane Maxwell, he uses the power stations there to attempt to destroy the trio in a literal trap set especially for them. Jane, however, destroys the power stations, severely weakening him. The trio defeat Berserk again, who is extremely embarrassed by his defeat. Before returning to the Photosphere however, he is killed by Boomerang, who comments on his failures and slices him in half with the Saber Fang.
In Alter Code: F, Berserk returns to do battle with the trio a final time in Malduke, having been revived by Zeikfried as a diversion so he could destroy Filgaia. He is defeated a fourth time.
In the original Wild Arms, Berserk has a long tail. This is absent in his character design in Alter Code: F.