A spin-off from Lys ap Adin’s AU "Five Things that Never Happened to Xanxus" (read that first). What if Federico had lived and Squalo’s duel with Tyr had happened on schedule? What would happen then? And how would Tsuna come into it?
Promotion, in the Varia, happened when a squad leader decided it was about time, or else when the person wanting promotion decided it was about time. The two usually balanced out. The question of who would lead the Varia, though, wasn’t left up to anyone but the one who led already and the one who wanted to.