Great thing to talk about! What makes you believe this, is it just because you like Kane or is it based off something else? Kane is probably the greatest "mindless" monster from WWE history, but I do not think he's better than Undertaker.
Its a strange viewpoint to have...because lets be honest...Kane was
originally a Michael Myers inspired "replicant" of the Undertaker.
I think (originally) Kane had a better look than the Undertaker...but
in hindsight Taker has always a better in-ring worker than Kane.
I'm more of Kane guy myself (the 2001 Royal Rumble being one
of my all time favorite matches) but then I think that simply comes
from my respect of Glen Jacobs and his body language & silent
monster performance during Kane's early years.
I'm a big fan of "suit actors" (Guys in monster/alien suits) & motion
capture acting...and I always found early Kane highly entertaining
to watch.
I mean I was that big of Kane fan that I literally stopped watching
wrestling once he first took his mask off & I didn't come back to the
product until I saw an image of Charlotte Flair late in 2016.