New Carinas Necro Challenges

G00SE_

So, I didn't play during the acquisition of Deathless Guillotine or Deathless King Groot. So, what are my options for doing this next set of carinas? Depending on the rarity of deathless pieces I purchase, I would have to spend 18k or 30k units, which is just not feasible. I don't want to pay $600 - $1000 to do content because I wasn't playing then. I've done the ccp challenges and a few necro runs. So, I wanted to try these challenges for what I would assume to be limited-time rewards (like crucible), or are the rewards from this set of carinas going to be around indefinitely? If that's the case, I could eventually farm the units. Last thing, if I did purchase the Deathless pieces I'm missing in a 6-star rarity, would I be able to complete the necro runs for a 7-star Deathless Thanos, or would I be limited to a 6-star Deathless Thanos? I would love some clarification from Kabam. Thank you.

Buttehrs

You don't really have to spend any money whatsoever to get them. Just grind arena to get units like crazy.

ahmynuts

You need all 4 deathless as a 7* to get 7* deathless thanos.

You only need the deathless for one challenge and it's for thanos