How to: Orochi AKA Top Light & Zone
Orochi is in a weird spot. Orochi has a bunch of different tools that are kinda useful at best. His strongest moves are the top light for guaranteed 2nd hit if the 1st in a chain connects and his super fast zone. Other than that you have a bunch of gimmicks/ 1-trick-ponies. If you want to play a samurai faction assassin then Orochi and the Shinobi are your go to. Orochi is not very useful in a team setting as he lacks tools and really is an opportunistic attacker. Don't expect to be able to do very well until you obtain gear, or have a solid foundation of skill.
First off your main methods of attack from neutral are very limited. You have your top light which is the fastest light you have, and your zone. All other basic attacks from neutral are far too slow to land if your opponent is even marginally competent. As an assassin constantly switch guards between directions your opponent is most likely to attack from (Ex. Wardens also rely on top-light and zone from neutral, so switch between top and left against them) to keep your guard from depleting.
The Top Light
This is your main attack as it has very efficient stamina cost for damage. It is fast, but not impossible to block/ parry so you will have to remain crafty to land this from neutral. As you most likely already know, if you land the first hit the 2nd one is guaranteed. Use it to react to GB for free damage. These 2 attacks won't be as strong as a single heavy, so don't use lights off a guardbreak unless you are worried about stamina cost.
Your only decent wave clear and 2nd best attack. Like the Warden it is extremely fast, but it is not punishable on block unlike the Warden. You can use zone to soft-feint any basic attack into a zone due to the 100ms input buffer built into the game, although flickering is equally hated and used amongst the community. Devs have said they are planning to remove flickering in the future so don't get used to it.
You have an enemy with 0 stamina guard broken, what do you do? You could go for a single heavy, but 2 are better than 1. Throw them to the side and switch guard to match throw direction. Throw 2 heavies in a chain as they fall and you can land 2 before they can block again.
Storm Rush Combo
Use Storm Rush to dash back and avoid an attack and release immediately so you can land it while they are recovering. If it lands successfully, they will suffer from a stun that allows you to switch to top guard and get a free 2x top-light in.