Shiva's Aid — When Hraesvelgr enters and whenever you cast a noncreature spell, target creature gets +1/+0 until end of turn and can't be blocked this turn.
Hraesvelgr is a mono-blue spellslinger-Voltron hybrid: cast a steady stream of cheap noncreature spells to repeatedly make one threat unblockable and pump it, then close with commander damage or a single evasive beater. Early turns develop card advantage and cantrips while protecting your evasion creature; mid-game you chain spells to slip a buffed attacker through every turn. The commander itself flies, has vigilance and ward, so it can both attack and defend while triggering off your own spells.
Repeatable unblockable enabling turns any creature into an unstoppable damage source or commander-damage threat
Vigilance plus flying lets Hraesvelgr attack and still block, and ward taxes targeted removal
Mono-blue gives access to the deepest card draw, counterspells, and protection in the format
Triggers off cheap cantrips you already want to play, so the ability costs almost nothing
Mono-blue struggles to interact with resolved permanents and lacks efficient creature removal
Heavily reliant on a single attacker—board wipes or targeted spot removal that beats ward stall the whole plan
Unblockable does nothing against players gaining life or stabilizing with fog/damage prevention
If Hraesvelgr is repeatedly answered, the deck loses its primary trigger engine and stalls
Turns your unblockable attacker into a card-draw engine, fueling more spells and more triggers.
Lean harder into one-mana cantrips and free spells (Brainstorm, Ponder, Gut Shot, Mishra's Bauble) to maximize triggers per turn while developing your board. Add protection and recursion for your attacker—Swiftfoot Boots, Heroic Intervention effects, and counterspell density—so a single removal spell doesn't end the game. To reach high power, incorporate a compact backup combo such as Thassa's Oracle plus Demonic Consultation or extra-turn loops so you aren't solely dependent on combat damage.