I don't know about Sapphire but Emerald has a stable amount of Necromancers walking around.
Also the players might just like playing something different
Necro's aren't only healers, they can be more roles depending on the skill build.
Now if you're having problems in "1vs1" fights, start amping or nightmare and dont fight at all?
Very appreciated
That's the set I used to use in dungeons, but now i've got another one which ill be posting shortly after/whenever I remember about it