White Lotus

White Lotus. (Comes at lvl 100) This one is only perfected 5s and 6s. 
Artifact: Same as Rahu's. (30% reduce+nully)
Mount: Same as Rahu's.

(Courtesy of EvermoreEm from Black Dragon)

Rahu. All 6s.

As you can see, despite White Lotus only being 5s and 6s, she is very close to Rahu stat wise. If she were all 6s, I believe she would be better than Rahu as far as stats go.