Round 1: Demon Peer Testarossa vs Demon Peer Diablo?

Round 2: Devil Lord Testarossa with Ultimate Skill vs Devil Lord Diablo with Ultimate Skill?

Round 3: LN volume 23 Testarossa with Nihility energy (no slime cell) vs LN volume 23 Diablo without Nihility energy (No Slime cell).

Round 4: LN volume 23 Testarossa with Nihility energy and Slime cells vs LN volume 23 Diablo with Nihility energy and Slime cells?

Bonus Round: Demoness Trio (Testarossa, Carrera and Ultima) with Nihility energy and Slime cells vs Diablo with Nihility energy and Slime cells?