Characters that are personable or have a notable personality despite not having a visible face. In other words, they are NOT just stoic.
>>1546482343 guilty sparkmaybe sauron from lord of the rings?maybe robocop?
(actually robocop is very stoic, nevermind)
gladOS and wheatley from the portal series
The requirements are ill-formed. For example, both glados and wheatley have very articulate and emotive faces replicating many features of the humans. Compared to them, shodan for example would be having less of a human face, despite having the likeness of one. Perhaps you should either consider only entirely unseen characters, like a narrator from stanley parable or AM from I have no mouth and must scream, or disqualify any character capable of articulation.
>>1546482That kid with the robot head from zero escape zero time dilemma.
>>1546515What about simply characters who wear a mask or helmet all the time?
Serious and mysterious != stoicespecially over time as character development occurs
Bionicles.