I collect many shards aim to buy ninja since i own druid and champion by using gem but now TG is a new hero
so what should i buy first?
If you're big on arena fights (especially with that champ of yours) then you can go for ninja as he is absolutely a game changer in arena. If you want more raid potential, TG does an amazing job at that with his skill. Your choice, arena or raid potential.
That's not to say ninja is "bad" at raids, he can still be useful if deployed properly and do some nasty damage.