Aun'Shi
He is awesome.
That is all.
What you want more?
Really?
Do I have to?
Fine.
The Bringer of Victory, Aun'Shi
Aun'Shi is another Tau Ethereal, Philospher Warrior Monks, who lead the the Tau Empire down a path of enlightenment (At least that's what they call it).
Alongside, just being generally charismatic, Aun'Shi has mastered the Art of duelling with the Honour Blade, that weird two-bladed staff that the Ethereals (And only the Ethereals, seriously, mount a power version on a Battlesuit, it'd be badass), to the point his name literally means Victory.
He was on his last tour of 'duty' before retiring to a paradise world, Aun'Shi was sent to bolster/train the defenders of a relatively new colony named Kel'tyr, which was founded on a planet infested with Orks which usually isn't a good idea, but the Tau had being doing well enough, Burst Cannons & Railguns are kinda awesome like that.
Unfortunately as he was completing his tour of duty in the Fio'Vash, a horde of Orks surrounded the compound, besieging the Tau, and beheading their leader. As the Fire Caste began to run around like headless chickens with the death of the their leader Aun'Shi proved himself to be stone-cold, leaping into action and splitting the Ork Warboss from scalp to groin, his Honour Blade stopping just above the ground as the Ork Warboss fell to pieces.
However the Ork Hordes rallied and began to send wave after wave of Boyz at the compound, where Aun'Shi set himself in a bottleneck and just killed each Ork as they rammed themselves against the door like a particularly bloodthirsty Laurel & Hardy sketch.
When a Relief force finally arrived at the besieged compound they found the Orkz scattered to the winds, piles of of the Greenskin's corpses choking the entrance to the last standing building where Aun'Shi stood in the doorway, his Blade soaked in ichor & gore as the last few surviving civilians huddled behind him.
Because he was so badass for what basically amounts to a 60 years old man, Aun'Va (The Space Pope) decided to revoke his retirement, and put him into the Tau warforce permanently, where he has been elevated to the position of a living miracle, and bringer of Victory, mostly because he has never stopped hitting people with his bladed stick.
Tabletop
He's the Tau's second melee character (after Farsight), bringing both his interesting Melee style & a re-rollable 4++ Invulnerable Save, alongside an Ethereal's massive Bubble of Buffs, however he's not overly competative, and more just a fluffy character to be used if you've got points to sink on an Ethereal that might need to be more survivable, I wouldn't skip him over, but use him for casual play at most.