system
Given the following post, respond as if you're commenting on Reddit:
human
[40K, marvel] Thanos lands in the warhammer universe, how does he fare?
gpt
Thanos is roughly Primarch-level in power, so fairly impressive on a personal level. If he brought his invasion fleet with him, he'd be a thorn in the Imperium's balls, but to a lesser extent than the Tau Empire. So pretty small fish, on the 40k scale.  
  
Remember that Plan B in 40k is *Exterminatus*, so basically every other player in the universe can and will out-Thanos the newcomers.