I feel like Masamba would actually be some sort of special sweeper, being high in attack and speed but pitifully low in defense (And especially weak to light or celestial magics) His special move would 100% be a type of sweep attack that effects all ground enemies (Flying enemies would be untouched)
For this move, he'd continuously shoot in and out of the ground, slicing up enemies by morphing his hands into shadow claws
Because this is a move that effects all enemies, the damage is not too high, and is recommended only for use when there are a lot of enemies on the field. The move would have a 40% chance to add a 'bleeding' effect to make up for the damage it doesnt deal.
For Aryx's two, I actually have a good idea. One would be the utilization of his fire breath, which can manifest into a fireball spell that actually deals physical damage instead of magical, and adds a burn to the enemy. This physical over magical makes his fireball unique to magic-casting characters, but it's the only 'spell' he can cast.
His special attack is likely to be something dragon-related. Something along the lines of "Draconic Spirit", a special also shared by Terroka, allows the user to engulf themselves in their designated breath power and deal a large amount of damage to one enemy by using all of their strength against the enemy. Both have a 50% chance to add an effect to the enemy (Aryx's would add 'burn', Terroka's would add 'blind') Because of the strength used up, this also adds a weakness effect to the user for the remainder of the battle, or until they faint.
((I have a lot of ideas for exclusive attacks for these characters btw))