I spent a lot of time with Kotal while practicing for Fatal 8! He's awesome, can't wait to play more.
The highest damage combo I got in blood god was 74% with 3 bars! But you can get 60% with 1 bar, which is probably more reasonable.
As for whether doing a combo with damage totem and blood sacrifice (the damage buff) already activated is practical, you can actually activate both in one combo. Toward 1 back 2 xx totem, juggle down1 xx ex antiair grab (ground bounces), toward 2, toward 1 back 2 xx blood sacrifice. If you manage to land a hit right after, this combo plus the 60-74% variations will just about kill heh. Note that you can also end this combo with sunlight that can either be meaty on the opponent to drain life or on yourself if you need to get some life back.
For the red health regen totem, I tried finding a variation on the above combo that would let me continue it long enough to guarantee that the totem would give health back before the opponent could get up and approach me, but I couldn't. Hopefully with more time in the future we'll be able to do this.
Don't sleep on the defense totem though, it makes a big difference. For example, blood sacrifice usually takes 10% of Kotal's health, but with the defense totem out it only takes iirc 6.60%. So I think I might want defense totem out if I'm just hanging out in neutral just in case I get hit. Activation of any totem is only like 30 frames or so in total, so it's not a huge commitment. The bigger problem is that you can't have two totems out at once, so if you have defense totem out and then find a hit, oh well, you can't get damage or life totem out until after defense totem expires.
Parry just gives you huge plus frames, so you can start big combos out of it. This is huge for Kotal because his mixups in blood god are kinda crappy, so opening opponents up for this giant damage is not so easy. Parry gives you a way to open people up even while you're on the defensive. This is extra important because he has zero good armored moves in blood god. If you're being pressured heavily in blood god, it's basically parry or nothing.
War god is his best early variation imo. The sword gives really good range, space control, and mixups. There's a 2/3 screen overhead that chops through the air to knock down jumpers, a big sweeping low, and a swipe into an unblockable ground pound, but you can cancel before the unblockable's animation starts by holding up to be safe from neutral jumps and armored moves. He can also throw his sword with pretty slow startup on the regular version but nicer on the ex. Btw with sacrifice buff, ex sword throw does some crazy amount like 30%, I dunno. Like a silly amount heh. Anyway this variation gives him his best mixups as well as his best armored moves, since all of the sword specials have armor on ex. Ex overhead does 2 hits which is important because that means it beats armored moves itself and it causes a ground bounce into big damage.
Sun god was disappointing to me because of the way the command grab works. It does more damage each time it's landed in a round, up to a nice like 20-25% or so iirc, but it starts out at iirc 7%, something really weak. And it lets you cash out for some percentage of meter or life, but you need to spend an ex meter to get more life. It's very important to sun god's strategy to land the command grab 3 times because otherwise it doesn't do good damage and doesn't cash out for good enough meter or health. The opponent will know that and should default to jumping or other escapes, but unfortunately the rest of his mixups aren't strong enough on their own. On top of all this, the command grab's range isn't spectacular. FerraTorr's command grab has enough range to work at round start positioning, but Kotal's is nothing like that. So, I feel that this variation is his weakest.
I'd say war god is the best, at least early, because it gives him the most options to open the opponent up, lets him worry less about being pressured, and gives him more space control. But if we can make blood god setups legit and if his footsies are good enough on their own, I can imagine blood god becoming better for at least some matchups. We'll see!
Speaking of footsies, his normals have incredible reach and hitboxes. Toward 2 is that big launcher. It's not safe, but it crushed through all the buttons I tried it against and it antiairs into huge damage from the right spot. Toward 1 works from about the same range, and the toward 1 back 2 string is cancelable, unlike toward 2, so it's important in footsies. Back 1 is a bit safer in footsies and has good range. Stand 4 is a huge boot that antiairs and pops the opponent up. Down 4 is like a Ryu crouching medium kick looking thing, great speed and hitbox. Down 1 is only 5 frames on startup, which ties it for fastest normal in the game. The downside is that his big midrange starters are unsafe on block. Part of why I like war god is that it lets you cancel toward 1 back 2 into sword for relative safety on block. Without it, I think he's probably more of a whiff punish character than an active pressure character.
So he seems quite varied, which is great. Blood god is weak mixups and defense but giant damage/extra life in the neutral game. War god is more midrange control, better mixups, and safer defense but less damage. Sun god is... I dunno, kind of in between in a way that I don't think is very strong. I first looked at Kotal because I love command grab characters but now I find myself not even liking the one variation he has a grab in, heh.
It's really tough to say how strong he'll be so early of course. I talked with some testers who don't think he's that great. But personally I feel that he has potential. I'm not sure how footsie heavy the game will be, but if it is, I think that'll benefit him because of his huge footsie range and damage. If not, maybe he'll have trouble, especially in blood god with no armored moves.
Anyway, lots and lots of fun, can't wait to get back into the lab with him!
but still.