Try it in joust first

I'm currently rank 7 Izanami and tried a couple builds for the first couple weeks of he being out but this build can't fail you. My advice is to stay quiet early, just farm and never start a fight before level 13-15ish. All u need is 2 crit items, usually sell transcendence to pick up bloodforge but any of those bonus items would work, transcendence is supposed to just help your mid game so you can get to late game quicker, it provides mana for her which she is a very "mana hungry God". Level up your 2 first because not only is it good with wave clear like her basic attack, but it also doesn't good damage and a very good slow. If you do start a fight, use your 2 then 1 and run them down with your fatalis. Your ult is good is certain situations, chasing people, ganking people, are good, and always lead the ult do hit your enemy.