How are rainbow adventurer's tickets obtained?
In the shop there is an option to buy 4★ heroes with rainbow adventurer tickets.
How can these coupons be obtained?
While the icons are the same, there are two types of rainbow tickets available. The adventurer ticket, which allows the choice of any 4★ character from the Special Shop and the Gtd 4★+ ticket, which is rewarded for various actions in game. The latter can only be used to get a random character from the Gacha Ribbon.
The only way to obtain the first one that I've seen so far is as Rapitor mentions, by purchasing the "Start-Dash Pack" for 400 paid Iris. This is only available within 3 days of starting the game.
Apart from that, you can purchase the Gtd. 4★+ tickets in the Seiros & Dulb Exchange. You can purchase up to 10 per month for 50 Dulb each.
Additionally, you can get them from quests...
Some examples of the quests that award the rainbow adventurer tickets:
- S Clear Ais Ep. 19 (VH)
- S Clear Lefiya Ep. 19 (VH)
- Log in for 30 days total
- Limit break Adventurer Bell (Final quest of Rookie Questline)
- 7th Day of login streak
You can purchase one as part of the starter pack, but after that. they are rewards for special events and quests.