Ok wrote some tips for Nioh PvP based on my experience with playing online.
Video version:
https://youtu.be/Bx9i4-sTYw4?list=PLv28sBtafuHN3e5gb7YD1DeRY1ZukB2Sl
TL;DW
I am not the best player in the world, but I feel like I can handle myself fairly well in PvP and people asked me make a guide so here it is ;D
I stopped PvPing for now, but if you want me to help you you can pop in one of my livestreams and ask for a friendly sparring to receive a live critique or even just playing for fun.
Twitch:
https://twitch.tv/sephizack2
First, this is not exactly a "tip" but you can go to online settings and change matching area to limited to help with lag. This is not flawless and if you live in a continent with few players it might take a while to find a match, but if you don't have that issue it will help you greatly.
If your opponents has a much higher level, more buffs or a heavy equipment, don't trade hits. When two people just run towards each other and start attacking, the one with more levels or buffs or better equipment will win. This is where the "PvP is unbalanced" comes from.
You want to play fast; many of those people will think they're invincible and start using long animation skills or play unsafe. You want to keep dashing around them (not running away) dodging their attacks and punish as soon as you see an opening. By punish I don't mean run up to them and start your 4-hits combo, but I mean quickly dash to them WHILE they are mid-animation, give a hit and then dash back. By timing this correctly (assuming low lag due to restricted matching), you will be able to land a hit without receiving damage. Don't worry if you do, you don't have to do it perfectly and I certainly don't do that perfectly but this is 100 times better than mindless attacking which will never help when you're outmatched in build. I personally played against plenty of people that were way higher level than myself, with way more buffs and better build and it's still possible to win. The scariest people I got matched against were Semtex_Jack and Callous_Bane and have won/lost half of my dozen matches against them. It will be very close and hard and one mistake will get you oneshot, but even in loss you can still make it hard for them to win.
I noticed lots of people that don't pay attention to their Ki. During a fight, paying attention to your Ki is in my opinion MORE important than health. Even if you have an advantage, DON'T initiate a fight with way less Ki than your enemy. In the video you can see plenty of times where the enemy started attacking me with almost no Ki left while I had plenty of Ki. It's easy to just backstep, dash into their face again and give a single attack to make them run out of Ki for a grapple. A successfull grapple can turn the match in your favour if they run out of Ki and viceversa.
Tip when you are against kusa/dual spammers. I noticed a lot of people get angry at the players that will just use the same skill with 2 seconds of animation over and over again without doing anything else and when you think about it, those are actually the easiest players to deal with. You already know what he is going to do, so why do you run up to his face and start your 3-hit combo?
What you want to do is bait their skill while you are in close-mid range and backstep as soon as they use their skill (or even before to play it safe). They will start their skill where they spin for 2-3 seconds while being vulnerable. You have plenty of time to EITHER shoot an arrow and backstep again (they will probably use the same skill again), or dash into their face as the skill is finishing, give one hit and then backstep twice (they will probably use the same skill again and you're very close).
Really, the only Kusarigama user I recall having problems dealing with is Semtex because he spiced things up after a bit and because he has many buffs. Overbuffed enemies are the ones you have to scared of, not predictable users who will only use one skill.
Ranged weapons. If you guys aren't lagging, please don't use your ranged weapon against an enemy who is not in attacking animation. Ranged weapons are easy to guard/dodge if there is no lag. The only times I got hit by ranged weapons (if I wasn't in attacking animation) was because there was so much lag the guy was shooting into my past, present and future at the same time. Most of the other times I can just guard or dash diagonally while closing the distance to punish them. Same thing happened to me. Whenever I missed a shot and they got close I was either hit or forced to guard and backstep. Ranged weapons have openings both while changing from melee to ranged and while changing back to melee weapon.