The Omenkeel is the reverse side of a modal double-face card published in Kaldheim. It is a vehicle whose capacities are:
Whenever a Vehicle you control deals combat damage to a player, that player exiles that many cards from the top of their library. You may play lands from among those cards for as long as they remain exiled
Having a 3/3 for two mana is already interesting in mono-blue. This ability allows to play a small enough number of lands to continue playing lands from the exiled cards.
Crew 1 :
The low prerequisite for the Crew ability is very interesting and allows to play utility creatures because they will be profitable by this ability.
Tips and Tricks
The Omenkeel virtually gives haste to creatures; Playing one before each attack phase inflicts more and more damage on the opponent.
When the deck faces an aggressive opponent in the early game and the first turn is played by the opponent, swapping into Hakka, Whispering Raven slows it down and builds a solid line of attackers. Hakka also allows the deck to advance after an attack if necessary. Alrund at the end of the game ensures a constant flow of cards.
The game plan is shared by other commanders: Kira, Great Glass-Spinner, Vendilion Clique and other mono-blue decks based on creatures.