Magnus the Red {3}{U}{R}
Legendary Creature — Demon Primarch
Identity
Izzet
EDHREC rank
#6,388
Cheapest printing
US$9.08
TCGplayer
Printings
2
Flying
Unearthly Power — Instant and sorcery spells you cast cost {1} less to cast for each creature token you control.
Blade of Magnus — Whenever Magnus the Red deals combat damage to a player, create a 3/3 red Spawn creature token.
Keywords: flying, blade of magnus, unearthly power
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
In short
A Commander deck is a commander and 99 other cards, one copy of each (except basic lands), all inside the commander's colour identity. Paste a full list into the deck price calculator to price it and check it against the format.