I had a 4/7 agonarch rune and just had to run it once on each of my three characters so that I could charge it and get the final calicified fragment for Touch of Malice. But, me being the dumbass I am I forgot to transfer it over to my second character when I killed the unique enemy. So now the only way I can get the calcified fragment today is by joining someone else's fireteam with a charge Agonarch rune. If anyone is generous enough to offer a spot up I will pay it forward by inviting others to my fireteam when I have a charged agonarch rune.
-
I believe you can still switch it... the daily unique enemies will respawn.... i have fought them multiple times a day but they only count toward the agonarch rune once per day