If you would draw a card, exile the top two cards of your library instead. You may play those cards this turn.
Eruth turns every card draw into double-digging impulsive card advantage, exiling the top two cards each time you'd draw and letting you play them that turn. You chain cantrips, rituals, and free spells into explosive Izzet spellslinger or storm turns, then convert that velocity into burn or a combo kill before the exiled cards expire.
Effectively doubles all your card draw, generating enormous selection and tempo
Synergizes with cantrips, wheels, and 'draw X' effects for massive impulse advantage
Cheap 3-mana commander that comes down early and snowballs immediately
Excellent at fueling storm, spellslinger, and prowess strategies
Exiled cards are lost if not played that turn, so you must commit mana or waste resources
Replaces normal draw, which can mill you out or strand expensive spells you can't cast
Fragile body that dies to any removal, halting the engine
Vulnerable to graveyard/exile hate and effects that punish casting many spells
Can be hard to hold cards reactively since everything is dig-and-play-now
Drawing seven becomes exiling fourteen cards you can dump all at once.
Add fast mana (Mana Crypt, Jeweled Lotus, Dockside Extortionist) and rituals to convert Eruth's velocity into same-turn explosive plays. Lean into a tight storm or Underworld Breach combo package with Aetherflux Reservoir as the payoff, and protect Eruth with cheap counters and Lightning Greaves. Tighten the curve so exiled cards are always castable, and trim clunky expensive spells that get wasted by the replacement effect.