A shame really, i was looking forward for the Danzo Izanagi bt lineups to find some more creative than mine but i guess there's not much to do with him.
I'm the only one using him in my server and i use the following lineup below.

It's great, basically use Mabui on Danzo in round 1 and you'll have him & Kabuto ready to go in round 2.
If they somehow kill your main Kabuto will bring her back and you reset your whole team.
If the enemy is faster than you and cc's you, you reset and launch.
If the enemy cc's the main, wait for Mabui's heal and reset.

There's many ways to play this, you can even use Kabuto pos1 and danzo pos2 if you want to, but from my experience you want Danzo as stacked as possible.
Why? Simple. Danzo's burst = His HP+his crit.
If the opponent's crit is much better than yours you won't crit and therefore you won't do the juicy 100k crit everyone looks for when you use this ninja.
Definetely go for his crit passive unless you're like in the top10 players of your server, if that's the case just go pos1 Danzo and enjoy the ride, whatever you target in turn2 is dead.

I'll be revisiting this thread sometimes just in case someone pops up with a better lineup than mine, he's definetely a hard ninja to use but he's most rewarding than most, in my opinion of course.