I would like a macro that on casts penance on mouse over and if I press shift, casts shadowfiend.
I would really appreciate it.
Tried making this macro on my own and turned the mouse over thing on in options but it wont work for me. 
/cast [mod:shift] shadowfiend;[@mouseover][]Penance
Can’t remember if penance is a heal/buff or attack ability so you could also change the mouseover part to either [@mouseover,harm] or [@mouseover,help]
The [] means “cast normally on my target”
Penance is an attack and a heal ability depending on who you target if that helps.
So I need to use penance offensively but also occasionally as a heal.
[@mouseover] by itself should be fine.
Or you might need.
[@mouseover,nodead,exists]
I will try it as soon as I am off work!
Needs the existence check if you want it to fallback to target when no mouseover is present.
so I was trying it out and it makes it unuseable in combat unless i mouse over an enemy, is there a way to fix that? I want it to hit enemies normally, otherwise mouse over my allies when they need it
Change the exists to help:
#showtooltip
/cast [mod:shift] Shadowfiend;[@mouseover,help,nodead] [] Penance