Hatorade
Sorry this got long with all the Edits but here you go.
I can't stand dual swords. I dunno yeah Sign of the Cross is cool and all, but kind of like Titanic Strength, it just gets boring after a while. And really Maraboshi doesn't show anything because legit it's completely pre made for you to cheese the fuck out of. Lay a paralyze trap and do your best "charge" skill: Sign of the Cross, Ia Quick Draw, Spinning Spear etc when they stupidly run right into it and freeze themselves. Also coupled with the fact that I just don't seem to "spec" them right. It's mostly because I absolutely hate investing into heart and that's a major chunk of scaling for both them and the other swords.
Throwing is amazing, if you keep it simple and that's what I stopped doing because I was listening to the min maxxers who take things to crazy complicated levels to just eek out a small % more damage. Go full Iga, inherit mostly just thrown weapon damage (not x2). make sure you have agility damage bonus and ninjutsu damage. AND snag Long Range attack, Kunai and Shuriken, and get the kunai and storm kunai specific buffs on arms. I'm actually working towards that on my ninja once I get my meathead settled.
And I can't say this specifically, but Axe actually destroys my other build right now. Their "on paper" stuff is off or something, because I rolled axe from the start, and I stuck with stamina so I could rock heavy armor and axe. Going in, I didn't care I was sacrificing damage, because I really wanted heavy armor. However, stamina REALLY scales almost better than strength on axes, so I stuck with that. I also joined the Todo Clan which buffs Stamina life scaling and further increases heavy armor wearing damage (forget the actual wording). I'm averaging 300 +38 on all my stuff and Titanic Strength does near 30k straight up and if I have weakness on the guy, it rockets up to the 50-60k range. And Lumber Chop is just dumb like 100k levels and I'm not even close to being optimized for chop, I focus on Titanic Strength. It's because of this, I stick with Axe. I could rock Duals instead of Axe and get roughly the same results, but you definitely need to focus on other stats (mainly heart skill strength) I like my axe/kusa and focusing on Stamina Body and Skill
That first video is from April 2017. Pre 2nd and 3rd DLC so it may be out of date. Lots of nerfs and newer armor sets, including graces changed alot of that up. I don't doubt that guy but he actually had one that was updated to reflect the changes from the 3rd DLC (which also includes the stat cap being 200 now). My approach though, is to never go all in on getting your core stats to 200 because you sacrifice utility in doing that. I stop at 150 and boost up magic, and some others that help with survival.
Edit 2: Ok just watched the whole thing. Dude's techniques are solid. He isn't just depending on SoTC, which is great. I love his combo of sign of the cross into the mob, then go into the wild blade thing. That is awesome. His parry skills are far above mine though so that would not be how my runs would look

With that said the Kusa has an identical move as the flurry, and it's just as potent. Even though it is outdated, I can testify to the absolute insanity that is Armor of the Exceptional. It is a powerhouse for damage. I'd love to use that, but the way I gear up (one piece of Tats is a minimum requirement for me because 100% RFA is a must), I have to use the spear, and frankly I like to switch between both weapons, and the spear is just too bi polar. When you can fully use it without bouncing off walls and rocks, and specs of dust (even with the mystic art), tornado is absolutely devastating. But it decides to get all "bouncy" in the worst of times so it's too unreliable. What I will do though, is take out the CCD on the weapons and put skill damage on instead. Holy shit balls I never knew there were diminishing returns on damage perks since it's just raw percentages.