Deadeye Triumphs seal and title were added in Season of the Lost. In order to get this one, you will have to master every weapon type available in game. Not the hardest grind in the game by any means, but still takes quite some time. Why not to just get a boost to save tons of your time, while we do all the job for you?
ETA for the boost is 3-5 days.
Available for all regions and platforms. Done manually, no 3rd party software.
Deadeye Triumphs seal boost rewards: