see, the common thing that both DS and DaS has is that there's isn't too much story to care about. The combat, world, enemies and bosses are just too awesome to make us ignore the lack of story base. Long time ago -> world fucked up -> demons popped up -> you are the hero -> save the world. As far as I know, the Great Grey Wolf Sif is just a guardian as a test of worthiness. You get the ring to face deeper despair, the fucking Four Kings. Just when I first beat Iron Golem and got to Anor Lando I was like, phew, half way of the game, but guess what? NO, It's just about to get started lol now when I look back. Wolf is probably my second favorite boss of the game cause first it's gotta be the Ornstein and Smough along with their superdopy music and cut scenes.
Long it's kind of hard to wear epic armor and roll like a ninja ... but I can tell you that there's a Ring (need Cat Covenant) that you can wear to have you keep your flexibility whiling wearing medium-heavy weight armor and also changing rolling actions (covering more area, invincibility). Hmm, I haven't tried wearing all the endurance increase gears and rings all at once.. maybe I can run fast in Havel's set.
About the Covenant, it depends on whether you wanna focus more on your online or offline game experience. For example, your dragon covenant will grant you the ability to invade others world who happen to have the dragon scale and if you defeat them you get more dragon scale which is very rare to get in single player but they are the only thing to upgrade dragon type weapons. Every covenant has three ranks, and you get rewards (rare items, armors, spells) but the requirement of leveling up is different. for you, you have to offer the everlasting dragon dragon scales to up your rank, and if you offer him ten then you will get another stone which will turn your body to dragon-noid lol. It's like a system to categorize online matches because Covenant are like servers in some way but not really. Once you are in the Covenant, certain actions will break your bond with your Covenant and you can't rejoin unless you clear you sins and it costs (you current soul level X 2000). BTW, you can cut off the everlasting dragon's tail to get a "secret weapon."
Yuan have you beat the game yet?
I wanna buy a recorder just to record my fight with Sif. It's too fucking epic.