Wow... that road to a million really messed up new player's progression.
I am happy you have a 5* Cable but your roster is now way ahead of your level progression. You really need to start doing more Story and get as far as you can (especially once you get to Act 4 tons of XP). Monthly events do not give as much XP. As others mentioned be sure to use your 40% and 50% XP Boosts when doing the Story Quests (also try to 100% Story too for the units and rewards).
Level 27 with the cats to rank a 5* but not the inventory capacity. Oh how the progress is accelerated versus back in my day. Take your 5* at level 27 and get off my lawn!!! Seriously though, like the other guys said, level up and your inventory capacity will increase allowing you to claim that cat. Nice pull by the way, Cable will serve you well as you do Act 3 & 4.
Comments
I am happy you have a 5* Cable but your roster is now way ahead of your level progression. You really need to start doing more Story and get as far as you can (especially once you get to Act 4 tons of XP). Monthly events do not give as much XP. As others mentioned be sure to use your 40% and 50% XP Boosts when doing the Story Quests (also try to 100% Story too for the units and rewards).
Hope that helps!
Good luck