Ragnar may not seem like an obvious choice for most Space Wolf players as they'd prefer to use Logan. However, In my recent battles I've found Ragnar to be far more useful.
I'll start as I have with the other SCs and look at his statline. It's a pretty similar story to Logan's apart from he's one attack short and comes with a 3+ power armour save. You might think he loses out but in fact since he gets a +D3 attacks bonus on the charge it isn't normally an issue. The lack of terminator armour means his unit can make sweeping advances which always helps! He comes with the standard Wolftooth necklace and Wolf tail talisman combo. His frost blade means he'll be hitting with an S5 power weapon (S6 on the charge) and melta bombs are thrown in for those opportunist vehicle kills. I doubt many people would upgrade him to have a couple of fenrisian wolves but the option is there and they are slightly better than the standard ones. He gets an invulnerable 4+ save too.
So what makes him worth your valuable points? Well his special rules are, in my opinion, better than Logan's. Insane Bravado gives you +D3 attacks on the charge and this applies to the whole unit. Imagine coupling this with a Wulfen grey hunter and you can see the potential. Further to this his War Howl gives the unit Furious Charge which once per game he can give to any units in 12". Now according to the FAQ this can even be used on the counter charge. So you get some BA charging you thinking they'll be hitting first and instead you all strike at the same time. Against most other enemies you'll go first and with the sheer volume of attacks you can dish out they'll stand little chance of hitting back. A full squad of 9 grey hunters with a Wulfen and Wolf Guard could dish out a maximum of 60+ attacks at S5 (or above)! Add in a Wolf standard and for one phase you'll hit with most of them, potentially you'll have wiped out a mob of 30 boyz after sweeping advance. Oh and Ragnar's saga means he gets bonus attacks if he kills a lot of things. Assuming he gets 8 attacks on the charge, he'll hit with 5/6, wound with 4/5 so that's a hefty bonus if there's anything left after the initial round!
I'd always put him in a decent sized squad and mount him in a transport. A rhino is the obvious choice for grey hunters. Let your opponent de-mech you then charge in and wipe them out. My preference however, would be a drop pod. Aim for one of his valuable squads or for that lonely troop unit sat on an objective right at the back. Obviously you can't charge straight away but if you rapid fire a squad nearby you're sure to attract attention. When your opponent comes into charge you can probably make short work of most things on a counter charge and then you're free to roam round the back of his lines. Obviously, you'll be attracting a lot of fire but with a decent sized squad you'll be fine. Remember if your enemy is firing everything he has at that one squad then the rest of your army can do what it wants! Finally, you could stick him and his squad in a land raider but just Ragnar and the LR comes to 490pts so it's hardly a cheap option!
I think it's probably clear from this post that I'm a big fan of Ragnar but there's still quite a few special characters left to discuss. Next I'll talk about the most unique of them: Bjorn the Fell-Handed.