"Buddyfight Intensified! Sengoku Academy!" is the 25th episode of the Season 1 anime. The opening and ending themes are updated in this episode.
In order to rescue Kiri, Gao and his friends go to "Sengoku Academy", a school that exists in the mountain recesses of Chou Hakone, They carry the absolutism about Buddyfight, a school that thinks justice is winning. They take Suzuha’s sky room there, but are attacked on their way by Sky Ninja, Yamigarasu, only to be rescued by Genma who then joins their mission.
Upon arriving, they find Rouga Aragami, who states they must win a 5 vs 5 match against him and ‘The Four Demon Commanders’. The first match is Rouga vs Tetsuya, who shows Asmodai's Buddy skill, a banana-shaped flying board. Tetsuya's hand has only one monsters, but after casting a Nice one! he gets what he claims to be a perfect hand to perform a One-Turn-Kill. Tetsuya casts a large amount of spells and calls Fallen Angel of Rage, Beleth to increase his gauge to 6 and reduce Rouga's life to 6, and during his final phase he casts 2 Diabolical Hardcores in a row to finish Rouga, but he dodges it with Phoenix Wall and casts several Bold Retaliations to increase his gauge.
Rouga's turn starts, he shows his improved deck and Cerberus' evolved form. Using the Gauge he accumulated he equips Demonic Spear, Swirling Darkness and uses Cerberus' skills to increase its critical to 8. He then casts Drill Bunker!! to increase Swirling Darkness' critical to 10 and attack with Penetrate damage, Tetsuya tries to defend with Solomon's Shield, but Rouga nullifies it with Fanged Dragon Declaration, effectively achieving a One-Hit-Kill.