I Kept Pressing the 100-Million-Year Button and Came Out on Top, Vol. 6 (light novel) — Syuichi Tsukishima

'TIS THE SEASON…FOR DUELING?!
After putting a stop to Raine Grad and ousting the Black Organization from Daglio, Allen barely has a chance to catch his breath before Claude transfers to Thousand Blade Academy. Things get even more hectic during the school's annual Christmas Party, which includes the much-anticipated Crush Your Crush Competition! Just a few days later, Allen is invited to the Liengard New Year's Jubilee to meet his nation's empress. But when a demon in league with the Holy Ronelian Empire attacks the gathering, it's up to Allen to fend off his deadliest foe yet!