Could have several causes...
did you define a starting position (characters properties) for this npc?
and as it is a npc I guess you did not include an image for all directions - is the character facing in a direction you got an image for? (you can delete all directions of your outfit that you don't need)
I don't understand what you mean by showing the character before starting the game. None of the characters are shown in the scene before starting the game? Is the NPC a character or are you using an object as a character?
If you are using an object, then forget about the starting position and direction. Then it is most likely that you forgot to set your animation as default animation or you have set the loop to 1 (default setting) instead of infinite.
If this is not helping, maybe you could post some screenshots of your settings of the character, so it's easier to find the problem.
For quicker help - most of the users are more active on discord