Devan Shell is the main antagonist of the Jazz Jackrabbit series.
Devan is an evil scientist trying to steal a princess and a magical gemstone which holds a great energy source, and wants to use this gem to take over planet Carrotus and the Galaxy. In a bonus level he appeared in hell as a satan/devil like boss. Normally he isn't into close combat, and lets his minions take the hits for him.
In M.U.G.E.N, Devan Shell has been made once by Dark Ruler.
Dark Ruler's version
Dark Ruler's version of Devan Shell is based off of his appearance in Jazz Jackrabbit 2, and features the name used for him in the game's level editor, Devil Devan. Like all the bosses from the game, he does not flinch when hit, and behaves similarly to how he did in the game, jumping around and shooting bursts of fast, powerful projectiles that travel straight forwards. To make up for his incredibly limited move pool, his attacks deal very heavy damage.
When his health reaches approximately half, he transforms into a more demonic and dragon-like form which flies and shoots fireballs which travel diagonally. He also moves much faster in this state, and tends to stick close to their opponent. The damage this form does is truly fearsome, and can KO a character in about six or seven hits, and cannot be blocked.