It's primarily durability. I just added a massive HP increase medallion to one of my 3* M tanks and the repair time jumped up to over an hour, when it had been less than half an hour the previous battle. No rarity, level, or type change involved.
It's primarily durability. I just added a massive HP increase medallion to one of my 3* M tanks and the repair time jumped up to over an hour, when it had been less than half an hour the previous battle. No rarity, level, or type change involved.