Chaos is always better if you have 10 humanity (Chaos damage scales, max at 10 humanity).

As for the damage, search for a Dark Souls wiki. There's one on Wikispaces and one on Wikidot, both which have the information you are looking for.

Remember to say your level (I can't help you, the only character I have at that point in the game is 10).

But to kill him, you should stay EXACTLY to the right or left of him (after breaking the crystal of course).

Then he can only hit you with his rare 360 degree crystal attack (which I'm not sure exists, maybe what I thought was his back was actually his front), and his less rare tentacle bash (if you tend a bit towards the front of his body rather than the back, he won't use this very often, breathing crystals at you instead).

You CAN leave Anor Londo after arriving, just talk to the gargoyle who carried you there in the first place.

As for leveling, Anor Londo is a nice place to hunt, but I suppose, being at the first bell, you probably want souls to make it easier. So one good, early, place for soul farming is Darkroot Garden, buy the Crest of Atorias from Andre the smith, open the door, then run a quick circle to aggro all the human enemies in that area. After that, stand between the stairs and the cliff, and they should all jump off the edge for a quick 7k souls.

To make the game easier on yourself, focus on gear. I have beaten the game at level 10 (solo, no summons). You NEVER need to grind, and NEVER need to level (beyond base requirements for the equipment you want to use).

For an easy good weapon, go buy a bow and a few hundred wooden arrows from the merchant in Undead Burgh, then go shoot the Hellkite Dragon (Undead Parish) from the doorway near the rats until you see a message saying you got a sword. This is an ok sword, but nothing too impressive.

If you are more ambitious, get your weapon of choice up to +5, find a green titainite shard (they can be dropped by slimes in the Depths) and then head to the Catacombs to find the smith who can make you a fire weapon.

Also, remember your shield. The second highest stability medium shield can be found from Baldar Knights (the red capes guys in Undead Parish), once again, remember to upgrade it, and a close runner up can be found from the Undead Warriors.

As for armor, a good, early, set for mid-weight and defense can be found in Darkroot Garden, explore the area with the stone golems for a while and you should find it. As with everything else, UPGRADE!

And of course, if you have humanity to spare, summon. There are plenty of players who create low level characters with end-game quaility gear to help new players.

You don't have to abolish sins unless you betray a covenant (switching, even if not through Oswald, doesn't cause sin).

But yes, you're free to rejoin covenants after switching, you do lose your covenant level though.

Favortie: Gwyn. Without using perfectly timed parrys, he's hard, but with them, you look like a boss. I play the game at level 10 or lower, so yes, getting one-hitted (or two hitted without many openings to heal) makes him hard.

Least Favorite: Capra, that's just cheap. I guess it's nice that they vary the exact style of bosses, but mobbing you immediately in a scenario that results in either instant death or an easy win is kind of stupid. Also, I hate Capras, why did they have to choose them as the one early boss that respawns the most?

I'm pretty sure the formula for invasion/co-op is your level +/- 10+10%.

I've heard that the Dark Anor Londo Blade of Darkmoon invasions have no level limits, but otherwise, they will.

I would recommend just making a few characters solely to co-op and just leaving them at low level builds.

I rarely rate messages as anything other than -.

So many stupid, completely worthless messages have high ratings (800 for one which says "bonfire" right on top of the firelink bonfire, no **** that's actually UNHELPFUL because I waste my time reading it and it clutters up the bonfire if I'm trying to rest).

And any useful messages never get rated so I never even see them.

It depends on the area and your level.

For Undead Burg, try being level 1-15 for co-op.

Don't even try to co-op Chapel (I've had the worst luck there), but if you must, sl 10-15 is good.

The Capra Demon is around 15-20.

Depths are best around 20.

Blighttown 25-30.

Sen's 30-40.

Anor Londo 40-50.

And the rest vary quite a bit.

Remember to place your sign near a bonfire (for most maps), those tend to have higher density than other places.

Also, there are multiple Dark Souls servers, so cycling through them (relay your sign) will help.