I remember reading this comic when I was a child. I think (but am not 100% certain) that it was published in the defunct magazine Hello Bédé, between 1989 and 1993. Most likely after 1991.
My memories are very vague, so I am unsure about the drawing style, as I may be conflating memories from several different stories. There is, however, one scene that I remember with high precision:
There is a group, lead by an old men, walking inside some structure which may be a cave or a high-tech building. They all move to a circular teleporting platform, all pronounce some magic formula, and disappear in a flash of light. One of them remains, saying something along the lines of:
“Dammit, my tongue twisted again.”
Then the story focus moves to another main character. After a while it goes back to the group of mages, who first appear, translucent, into a different place. They materialize, and prepare to move, while one of them remarks:
“But where is (name of the guy who failed to teleport)…”
…just as he appears in the transluscent form, saying:
“Here I am, here I am.”
A bit later, they confront some bad guy or thing, and the leader of the group does some magic again, invoking:
“…by the Great Melchior.”
This is all I remember. Anyone could help me solve this riddle, which has been bugging me for years?