In the Tower of Lost Souls mode on the Ascend path, two Skeletons who share the same fighting style but have different articles of clothing appear in two different floor challenges. Both wield different weapons, have different skill sets and have different upgraded attack, defense, and HP gauges. The first one is relatively easy to defeat, but the second one is somewhat harder to defeat, most likely because of the upgraded gauges and the computer trying to ramp up the difficulty.
Tower of Lost Souls Details & Skills
TOLS Ascend Floor Challenge: Life To Entertain (Floor 16)
Skills: HP Drain A
TOLS Ascend Floor Challenge: Irritation to Ruin (Floor 41)
Weapon: Soul Edge
Skills: Venom Fang S
Shave Damage A