I understand that this can be done with tweening, but with all of my attempts it does not really feel like it is properly going upwards to the player, if there is also a way to make the line bend that would be really helpful (I don’t think that is possible tho).
“A diagonal line” is really vague.
Do you mean in a Gui?
Or a Part in the workspace?
Or a ray?
Since this is scripting support please explain exactly what you are trying to do so we aren’t guessing, and please include your code so we can understand that as well.