Hades: All Companions & How To Get Them

"You don't have to be alone fighting your way out of the underworld. Hades actually has companions, which are items that can summon a friend into battle for a short span of time. Such friends can be useful for boss battles, and the companions can be leveled up with Ambrosia to increase the number of summoners per underworld escape attempt. To fully upgrade a companion costs 10 Ambrosia in total to increase its maximum summons to five." - click image for article