Its Bloodthirst ability lets it come in with +1/+1 counters based on damage dealt to your opponents, and its Enrage effect lets it deal damage to an opponent, each time it takes a hit, unless they sacrifice a (non-token) creature
The caveat is Medomai can't attack during extra turns, meaning you need ways to get around that pesky restriction
Here's its reminder text: (To forage, exile three cards from your graveyard or sacrifice a Food
Reckless Rage is a four-of in the deck and isn't especially replaceable since it offers not only incredibly efficient removal, but another way to target your own creatures with a spell to grow heroic threats like Favored Hoplite and Tenth District Legionnaire
A different build would be focused on blink and creatures that have good enter the battlefield effects and higher toughness than power, like Sea Gate Oracle, Brago, King Eternal, and Wall of Omens / Wall of Blossoms
Might want to go get your tetanus shots updated sometime soon