[@The One]
"Samurai Art: Eclipsal Night, this is just a simple art where the user creates a solar eclipse permently until the user is defeated or until somebody cancels it."
It won't be an actual eclipse, and it won't be permanent, it may be achieved by applying a sort of illusion, but blocking off the sun requires something a tad bigger than a city block, and it would never be permanent, so if you'd decide how you'd want to use it and set a time limit I'll look it over again.

Hero slayer and villain slayer will be effective based on morals, rather than the side one fights on. Means the attack might vome as surprisingly (un)effective, but there might also be people who don't take too much from either for being a bit grey on morals.

And portal jump is mostly okay, but I'll state this now; If the cut is intercepted by any physical form, it fails. So no opening portals in someone's chest and parrying the attack can stop your escape.

Now, as for the forbidden arts.

Not sure how I should envision the raindrop barrage, so uhh, yeah, will need to understand before I can accept it.

Then, soul link...You would probably need some sort of connection to the target previously, probably emotional, and I'd suggest the damage be split, rather than transferred. (Can't have you killing people by blinking at them and commiting seppuku)

AND FINALLY;
Having all Bakudo/hado spells would make your spell list a wee bit over the top (I mean quite a bit, really) as well as them being spells from a pre-existing canon, so I cannot accept these due to the non-canon rule.

[@Hammerman]
By now I'm running out of time, so I'll review your CS later.