#1 - March 5, 2018, 12:13 a.m.
1. Starcraft 20th Anniversary celebration has cross game rewards for every Blizzard game. For Diablo 3 we get Dominion’s Revenge, "a fearsome Battlecruiser-themed Pet". FREE. Just log in to Diablo 3 after March 6th to claim the pet. NOTE: This pet is PC only, not Console. Console will get it when the patch releases containing it but there is no ETA for that.
Details here https://starcraft2.com/en-us/sc20
2. Adventuring with Kanai and the Kanai's Skorn Transmog. This event happens every March and honors the memory of Kevin Kanai Griffith, a Blizzard staff member who passed away from cancer. Join Chief Kanai as he battles his favorite enemies. You can find him in the Elder Sanctum Throne Room in the Ruins of Secheron in Act 3 Adventure Mode. This is live now.
During March 24-31st you will also be able to loot a transmog axe from the chest by his throne.
You can read more about the event here https://us.diablo3.com/en/blog/20058187
More details about Kevin Kanai Griffith are in the Kanai's Cube intro article https://us.diablo3.com/en/blog/19817367