I completed the blue portal in Life Threatening Battle with 23k power as a Lightning main, this is the line up and strategy I used. (Note: Includes a Pain, so not fully Free to Play). At most, this line up will get you 1 death (Main or Hinata), if you're lucky, you will get through this with no deaths.

http://i.imgur.com/qSVIkur.png

http://i.imgur.com/9VcQ2YL.png
Talents: Using Anbu Tactics may be acceptable too. I've not tried it, used the Lightning Enhancement to increase damage.

Steps:

Round 1: Use Gakido's mystery on Hinata, activate Hinata's mystery. Ensure standard attacks will create a combo on Kisame to kill him off in the first round, if not, retreat before any ninja dies and retry.
Round 2: Use Kakashi's mystery on Sasori, Hinata's chase will accupunture Sasori. Ignore Hidan, he will kill your main's clone (very important to ensure it stays alive).
Round 3: Use Main's mystery on Kakuzu. Standard attacks should kill off Itachi here.
Round 4: If your Main is still alive, use Gakido's mystery on Main for shield protection. Use Kakashi's mystery on Sasori and try to finish him off here. Standard attacks should be able to kill off Kakuzu and/or Hidan in this round, do not worry if you don't, they will die from standards in the next.
Round 5: Use Main's mystery on Deidara, if Sasori if still alive the small AOE damage from Main's mystery should kill him. If Deidara does not die within this round, keep using mysteries on him and standard attacks will kill off Hidan when he revives in future rounds.

Hope this helps!
This post was last edited by Rikkain at 2016-10-18 17:23 This post was last edited by Rikkain at 2016-10-18 17:27