Valve has only just released Dota Underlords in beta, and now a new feature has been included, similar to the battle passes we've seen in various other games. The Proto Pass, as it's called, will let players unlock banners, emotes, and a new board type by playing Underlords, along with daily and weekly challenges.
More details can be found on the Proto Pass site, and Valve emphasises that this is "as learning experience for the Underlords team", hence why they want feedback so they can adjust plans in time for the Season 1 Battle Pass.
XP for the pass can be earned in every multiplayer or hardcore bot game, and daily quests will let you level up faster. With each level you'll then get a reward, and level 5 unlocks the Path to Sunbreeze board. Other rewards include respawn effects, firework effects, Yo's, and portrait rings, so it already has plenty of variety packed in there.
Have you tried out Dota Underlords yet?