User blog comment:Justin Holland/Flash Sesonal Nemesis-es compared to Arrow seasonal nemesis-es/@comment-27700324-20170227203308/@comment-24152851-20170228024210

Because they're both feared legends who predate the hero.

Arrowverse Ra's was really underwhelming though, who literally had his entire villiany motivated by following some rulebook. Liam Neeson's Ra's was way better than Matt Nable's.