Alrund gets +1/+1 for each card in your hand and each foretold card you own in exile.
At the beginning of your end step, choose a card type, then reveal the top two cards of your library. Put all cards of the chosen type revealed this way into your hand and the rest on the bottom of your library in any order.
Flying
Whenever Hakka deals combat damage to a player, return it to its owner's hand, then scry 2.
Cast Alrund as a mono-blue beater whose power scales with your hand size and foretold exile pile, then snowball card advantage every end step by naming a card type to draw two-for-two. You hoard cards and foretell spells, growing Alrund into a massive evasive (with the right enablers) threat while controlling the board with counters and bounce.
Generates relentless card advantage every turn via the end-step trigger
Power scales naturally with the big hands mono-blue draw decks already keep
Foretell synergy doubles as cost reduction and fuel for his +1/+1 buff
Mono-blue gives access to the format's best counterspells, card draw, and tutors
Alrund has no evasion or trample on his own, so a single chump blocker stalls him
As a commander beatdown plan, he's slow and easily chump-blocked or removed
Mono-blue struggles to interact with resolved permanents and lacks efficient removal
Relies on a large hand, making him vulnerable to discard and hand-size hate