I’ve watched the Boss Fights of the Koopalings and they seem to be implied to have just as much power as Organization XIII!
Larry Koopa is able to raise water to the top of his Airship’s command room and create Geysers that go up and down stably even when he is spinning in his shell all of which requires Demyx-level Water Magic. He also has a Wind Attack called Larry’s Tornado in Puzzles and Dragons Super Mario Bros Edition…
Morton Koopa Jr. has a flame attack and can create Fire Shockwaves… He may be the weakest Koopaling…
Wendy Koopa can create copies of herself using purple magic and they can use pure Magic attacks like Anti-Aqua and can even use a Spinning Attack like Anti-Aqua’s Dark Spellweaver Finish. Considering she and her copies can create Magic Rings that are extremely complicated it stands to reason she and her copies can use all of Anti-Aqua’s moves including the Dark Spellweaver Pearl attack.
Iggy Koopa in Puzzles and Dragons Super Mario Bros Edition has an attack called Iggy’s Hurricane. Hurricanes spread across a wide area so that means Iggy has Wind Magic greater than Xaldin! Surely he has the ability to use Xaldin’s attacks if he wanted to…
Roy Koopa in Puzzles and Dragons Super Mario Bros Edition has an attack called Roy’s Lightning which means he has Lightning Magic which we never properly see…
Lemmy Koopa in Puzzles and Dragons Super Mario Bros Edition has an attack called Lemmy’s Nightmare which indicates he has some Nightmare Magic. He also can teleport using Magic and uses his wand to create doppelgangers…
Ludwig Von Koopa in Puzzles and Dragons Super Mario Bros Edition has an attack called Ludwig’s Volcano which requires a mastery of Lava Magic.
Bowser himself has Dark Magic on a huge level which he doesn’t bother to take full advantage of. He can and has turned almost all the Toads of the Mushroom King into Blocks with Darkness and has on more than one occasion created dimensions of Darkness(Ansem only manipulated the one in Sora’s Nightmare) with Mines surrounding the Battlefield.
Bowser could if he wanted to create a giant ball of Darkness raining down Darkness upon his enemies like KH3’s Skoll can, send a rain of Dark Arrows down on them like Xigbar can, cause Dark Orbs to charge his enemies through the corridors like Ansem can and cause Claws of Darkness to attack them from the ground like Dark Riku and Ansem can and unlike them probably doesn’t need to even be physically present!
This also doesn’t go into the fact that Bowser can cover himself with an Earth Boulder and create Huge Earth Spikes out of the ground and can likely create Mesas out of the ground too.
Clearly Nintendo has made it blatantly clear that the Koopalings and Bowser have all been holding back and not showing their full power… And all despite the fact that Bowser attempts to grab sources of power despite never going all out even with this new power! Is Bowser and the Koopalings that lacking in intelligence?