Unfortunately Ninja is probably gone forever. He can't be summoned from shards but maybe if we're lucky they might offer him for a special event again someday. Don't feel too bad about it, he's a good champion but there are lots of others that are as good or even better. Also everybody who makes a new account will be in the exact same position you are in now.

It's my own fault, and it makes me feel bad.

I don't care what he was, useful or not. I ruined everything for myself...

try to make a support ticket see if they can help with this issue

I made it myself with my own hands....

I don't think they'll give me back Ninja.

Honestly, I think you should write Ninja off as a costly lesson.  Using him as food takes a couple of conscious decisions, and I think you are right to admit it is due to your own actions he is gone.

The best thing now is to look at what you can do going forward.  Maybe post your roster if you are having issues with something and we can help

The  good  news  is  you  don't really  need  Ninja.

I  beat  all  Arbiter  missions  +  Faction  Wars  mission's  with  out  Ninja.

I  am  currently  working  on  Ramantu  missions,  but  I  haven't  used  Ninja  to  help  me  beat  any  if  them.

In  addition,  you  can  still  pull  Ninja  from  Ancient  Shards.

So  its  ok  -  just  try  to  keep  going

You're missing the point.  Countless players have achieved Arb without Ninja, but it takes monehe if not a year.  He was able to get Ninja in a week.  That is huge for a new account.  However it was his mistake and he admits it.  You are correct in that Ninja is not necessary, just better to have than not have.

Second, you can NOT pull Ninja from ANY shard.

Cheers-

ive  Had  this  happen  before  In  another  game,  make  sure  you  try  to  contact  them  doesnt  hurt  to  try