I was legit shook when I looked it up today and discovered that they were actually still making songs and touring and not just living off of When Worlds Collide royalties.
I dunno, the one part that matches is essentially the main rhythm, bass, and beat of the Sephirot theme outside of the chorus (which also deviates in Powerman's song too). The singers do sing in a very similar tone, but that's more a work of the genre of this kind of music than anything else.
Personally, I think there
may be enough to at least commence legal action (cost/time worth and actually prevailing on a copyright infringement case like this is another story). But I mean... It's not like Soken decided to riff a 15 year old song to top the charts or anything like that as opposed to just making a song as you fight a giant demon of alleged tree-origins. Was probably meant for homage more than anything else.
On the other hand and with that said,
a composer who worked on Super Robot Wars K got 86'd a few years back for ripping off a segment of a song that RPG fans may blatantly recognize even though the segment itself was probably only 20 seconds.