You won't gain gems directly from talking on the forums, but you earn xp from your posts (only 5 posts per day) and when you level up you will get some gems.
The same I'm having the same issue I haven't received anything from Monster Legends after completing the task ;(.
in 3 steps
Choose the game that interests you and play itfor free.
Every game has some quests for which you will receive Soul Gems.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
You know that on Gamehag you can get real rewards for free, right? Join us, complete walkthrough and get your chest!
How do you gain currency by talking on here? And do I need to claim a reward for my Monster Legends task?