When it comes to Clawswipe Colosseum in Bowser’s Fury, everything on the island won’t be unlocked until you complete the three boss battles on the island one after another.
Once you have accomplished this, all levels of the island will rise from the ocean’s depths and unlock, among other things, all five Cat Shards you need to get the Cat Shine.
Once you have the entire island built, you will be able to find the Cat Shards in the locations down below.
Cat Shard #1
The first one is easy, located in a small pool near the entrance to the colosseum.
Cat Shard #2
The second one is even easier, located just under the arena in the centre of the colosseum.
Cat Shard #3
This Cat Shard will require you to be Cat Mario and to scale the inner wall on the Northern side of the level.
Cat Shard #4
Located at the very top of the level once the colosseum has fully formed.
Cat Shard #5
At the top of the colosseum, use the nearby spring to launch yourself towards it to collect it and finish the Cat Shine.