In Co-op mode, Aru's stats and passive do not change.
Aru's Hyper, Present for You, has a slightly different effect in Co-op. The Hyper will no longer grant stars, but otherwise functions similarly to its Normal mode counterpart.
Aru's passive and Hyper are unchanged in Bounty Hunt mode.
Aru's base stats give her 46 starting stars and a discount of -15% at shops.