You just need to have the timing down, delay it slightly so that when 5B connects the opponent is level with you. Takes practice, but not that hard.
As for combo, Izanami has a lot of variety in combos, but some simple ones I use:
2B > 5B > 5C > 2C > 3C > geki/deploy. Basic midscreen combo. Deploy gives you araragi oki, good choice for midscreen, while geki ender leads to corner combo: ~> geki > 5B > 5C > 6C > corner ender. Careful with your hitconfirms though, 3C is not special cancellable on block and it's quite negative on block you're sure to get punished.
6C/~> 5CC > hoko A. Gives decent corner carry. 6C starter is for low to high mixup, while ~> 5CC can be done from other starters like 5B. Comboing into hoko A from 5CC needs to be done without delay; there's no time for hitconfirming (though hoko A is only -1 on block so it's still safe even if you messed up). Another good thing about this combo is that if it's blocked, it makes a natural frametrap. Do another hoko A after this to catch rolls, and if the opponent emergency techs, you'd end up right beside them with some frame advantage. In corner leads to combo: ~> hoko A > 5C > 6C > corner ender.
6B > geki. Midscreen there's nothing much you can do after this without meter or deployed state. Same as the two above, leads to combo in the corner, though you can have it longer with 6B starter: 6B > geki > 5B > 5C > 6C > hoko A > 5C > 6C > corner ender. If 6B is blocked you can delay geki a bit to catch people trying to mash.
2B /5B> 5C > 6A > float > 5B > 5C > 3C > 9hjc > 5B > jc > jB aerial. Good corner carry but needs to be done close or the 6A will whiff. Also 5B needs to be delayed or 3C will whiff. I'm still not very good with the aerial part myself, though.
Front grab > Shizuku > 5C > Hi > dash jump > j.C > float > 5B > 5C > 6A > Kai. Actually this is not optimum yet, this is just copied from the famitsu video.
Corner ender: Generally it'll be hoko A > 5C > 2C > Hi > ender part 2, but for some characters you need to microdash very slightly or Hi won't connect, and for some characters it won't connect at all. In that case, just go straight to Hi > ender part 2, this works universally but you lose quite a bit of damage. For ~> 2C > Hi, hold Hi a little bit (until the opponent is about level with the flame) for maximum hit, damage, and untechable time. For straight Hi from 6C, release Hi immediately.
For ender part 2, the generally used is 5D > Tate > Araragi oki. You can squeeze a bit more damage with meter by using 6B > Kui. Or if you have good timing, you can even do dash > 6C > hoko A > 5C > Kui. You can also replace 5C > Kui with 5C > 6A > Kai > float > 5D > Araragi oki, though if your opponent has a reversal with good horizontal range this is rather risky.
jB Aerial: jB > jC > float > 5C > 3C > hoko A > 3C > 9hjc > jC > 6A > Kai > float > 5D > Araragi oki. If by hoko A you (you, not the opponent) already reached the corner you can follow up hoko A with 5C > 2C > 6C > 9hjc > 5C > 2C > Hi, the rest is the same as the corner ender stuff.
Za Warudo grab combo: 6B > Shizuku > 2C > 5C > hoko A > 5C > jc > j2C. I've seen people end this with 2C > 5C > jc > j2C instead but I never managed to get it to work. 5C > jc > j2C needs to be done very quickly or you'll jump off too high.
OD Za Warudo grab combo: 2C > 5C > 6B > hoko A > buffer shizuku > 2C > 5C > 6B > hoko B > 2C > 5C > jc > j2C. If you're on active flow, replace jc > j2C with 6B > EA, this'll give ~5900 damage IIRC. This is my favorite reversal simply by the fact that less experienced players will reflexively block when seeing OD used as a reversal because they're afraid of EA, but of course it won't work on more experienced player.
Also if you're in the mood to brag, Izanami can combo into AH from normal grabs (front, back, air), 6B, or 6C (even if only the 2nd hit of 6C hits).
These are just some simple ones, there are many more varieties like combos that start when you're deployed, or combos that have you deploy mid-combo, and other better-optimized combos. I'm not that good of a player so I can't do those combos myself.
