From the event thread:
So, it should be Monday. But since your chances of a random draw for a specific legendary are now dipping south of 1 in 6000 on average for glory keys (in reality, it could be much, much worse), don’t expect to get him any time soon. Luckily, he’s pretty mediocre, being below the power curve compared to nearly every legendary released in the last several months, in addition to both his trait and summon being really hard to make use of, so you aren’t missing much in terms of it being a “meta” troop.