The Rakshasa Baron (or Tony, as I'll be calling him for reasons I can't explain because of intellectual property laws) is a fascinating example of the new 'mastermind' concept for monsters in 4th Edition. At 75 points, he's clearly going to be the centerpiece of a 200-point warband, but he's mostly a support piece with Champion powers that reflect that role.
The first of those Champion powers makes it easy to use all those abilities that require combat advantage without all that tedious positioning and tactical thinking that's usually required to set up flanking positions. I kid, of course. You can use both Champion powers a combined total of only three times, so getting the most out of them requires plenty of tactical chutzpah. With that in mind, it's never a bad thing if you can walk up and get a Sneak Attack that eliminates a high-profile target without needing to fuss too much about it.
Tony's other Champion power is the more interesting of the two in the long term thanks to its open-ended non-specificity. You can recharge any old rechargeable power, even if it's usually only rechargeable in a "once per game" condition such as being Bloodied for the first time. The list of faction-compatible abilities that this can apply to is short at the moment, but it will grow and eventually become ridiculous -- mark my words.
When fighting for himself, Tony does pretty well provided that he can keep himself at a distance. He's helped in this by a slightly above-average Speed and (if you're doing this right) a warband full of allies willing to protect him. All of his attacks have excellent bonuses to hit, and Mind Twist in particular comes with a nice secondary effect.
When he does get into trouble (specifically, when he's Bloodied), Tony suddenly does a panicky rendition of a displacement spell, hiding from the enemy until they find him with the tips of their swords. He's been know to describe these moments as "Not so grrrreat!"Synergies
Rechargeable powers! Consider Lifeleech Otyugh, Yuan-Ti Champion of Zehir, Vampire Spawn, and Fire Archon.
If you do find a killer combo with one of Tony's Champion powers, the Delver Sergeant will let you squeeze one more use out of those powers.
Evil allies with Sneak Attack are an obvious way to capitalize on the combat advantage power. Right now, that's the Oni. To be honest, I was a little surprised to discover that the Assassin isn't Evil.
The Vampire Spawn's Blood Drain works only with Combat Advantage, and he's Evil. This should suggest something to you. If it doesn't, review Tony's card. I can wait.
On a more general note, make sure your warband contains meatshields, because your opponent is going to want to rush Tony as quickly as possible; you want loyal minions to get in their way.500-Point Play
Sure thing. Tony's attack bonuses are great, and he should hit the highest ACs and DEFs without too much trouble.