As long as your life total is less than or equal to half your starting life total, Myrkul has
indestructibleIndestructible is a static ability.
A permanent with indestructible can’t be destroyed. Such permanents aren’t destroyed by lethal damage, and they ignore the state-based action that checks for lethal damage (see rule 704.5g).
Multiple instances of indestructible on the same permanent are redundant. (CR 702.12).
Whenever another nontoken creature you control
diesIs put into a graveyard from the battlefield. (CR 700.4), you may
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) it. If you do,
createTo create one or more tokens with certain characteristics, put the specified number of tokens with the specified characteristics onto the battlefield.
If a replacement effect applies to a token being created, that effect applies before considering any continuous effects that will modify the characteristics of that token. If a replacement effect applies to a token entering the battlefield, that effect applies after considering any continuous effects that will modify the characteristics of that token.
Previously, an effect that created tokens instructed a player to “put [those tokens] onto the battlefield.” Cards that were printed with that text have received errata in the Oracle card reference so they now “create” those tokens. (CR 701.7) a token that's a copy of that card, except it's an enchantment and loses all other card types.