Count multiple tables as one count
I did not manage to delete my post from the phone. It's probably easiest to do each count as a subselect.

SELECT c.name
     , (select COUNT(i.character_id) 
         From wiki_items i
         Where   c.character_id=i.character_id

       ) as  wiki_unlocks
     , (select COUNT(a.character_id) 
         From wiki_armors a
         Where   c.character_id=a.character_id

       ) as  wiki_armors
     , (select COUNT(w.character_id) 
         From wiki_weapons w
         Where   c.character_id=w.character_id

       ) as  wiki_weapons  

FROM characters c