My first 5* and it's predator batman !

Finally after a long wait and with the new 1.5 patch hero promo. I now have a 5* 

Promo pops up at lv 40 via capsule promo

Also predator batman was the first to accept the 4* offer as well on day 1 when the 1.5 patch goes live

Personally predator batman is worth the 3.6k gem upgrade since grinding in arena is hard.

Current conversion of arena medals to shards is 10 : 1

Unlock cost 160 shards, 4* cost 200 and 5* cost 440. A total of 800 shards or 8000 arena medals to max.

With the average of finishing in elite 2 rank , 400 arena medals per week. I will be needed to stay at least for 16 weeks plus a mandatory 4 weeks is needed to unlock.

Being said as a casual player I rather use the arena medals to unlock new arena characters currently left 3, captain cold or horrific scarecrow being the next target.