Damn, and I had just finished tier 1... (EDIT: to clarify, I finished getting everything I would need in terms of content down. This is completely unedited, and likely nonsensical at times)

[hider=Tier 1]Tier 1: Narcis’ mind is flees his body if it detects it is in danger. After a successful escape, Narcis’ mind will attempt to find and suppress another being’s mind, and then take control of its body, making it a host for Narcis to live in. 

The mental takeover process is split up into the suppression of a mind and then maintaining control of said mind, both of which are dependent on two aspects of the mind in question: How intelligent it is, and how active it is. Say, for example, Narcis’ mind is within takeover range of a giraffe, a dragonfly, and a human being. The easiest target of the three would be the dragonfly, followed by the giraffe and human respectively. Narcis’ mind will always go for the easiest, most complex target available. Suppressing the mind of a dragonfly would be easy, as not much other than pure instinct exists in it. Staying in control of the dragonfly, however, is not quite so simple. Because of the creature’s low intelligence, the connection between Narcis’ mind and the dragonfly’s is very weak. Narcis’ mind needs to communicate with whatever mind it has suppressed on a subconscious level in order to control the body, and since the difference between the mind of a human and the mind of an insect is as vast as it is, certain commands simply will not translate. Situations that could cause Narcis’ mind to be ejected from the insect’s body would be if Narcis was particularly panicked or stressed while controlling the insect, or if the insect caught a whiff of a pheromone (or something). 
Moving on to the suppression and control giraffe, there will be some similarities and differences to the dragonfly example. Needless to say, a giraffe has a much more complicated mind than a dragonfly. If a dragonfly were panicked and in fear for its well-being, Narcis’ mind would still be able to suppress and control it. If the same were to be said for the giraffe, Narcis’ mind would have an immensely difficult time suppressing its mind. If the panicked giraffe was one of several options for takeover, Narcis’ mind would not spend time hijacking its body. If it were the only option, Narcis’ mind would have to forcibly suppress the giraffe’s conscious mind. This makes the giraffe consciously aware of another presence within its body, which would naturally panic it further. Usually this would forcibly eject Narcis’ mind, but if it has no other option for a host, it will itself go into a sort of “suppressed state” and wait until the creature’s mind is no longer in distress. Maintaining control of an animal such as a giraffe is much easier than controlling an insect. Once the creature’s mind is suppressed, only issues on Narcis’ end can cause his mind to be ejected. 
A human mind is one that varies significantly between individual beings. While all minds are universally susceptible to invasion when the host is asleep or unconcious, any aware human is a challenge for Narcis’ mind to take over. A conscious, intelligent person, would be impossible to take over unless they were stunned/dazed, whereas a less than intelligent person could potentially be seized by force. Only in a case where an alert person of moderate or lower intelligence is completely relaxed and carefree would Narcis’ mind be able to take over with little chance of ejection. Overpowering a human mind is incredibly difficult, no matter how intelligent the person’s mind is. At this tier, it is impossible for Narcis to overpower a mind that is aware of his presence. When it comes to staying in control of a human mind, there are many variables that can cause issues for Narcis. If Narcis takes over a man who has children, and one of said children attempts to speak to him, it will generate reactions from the subconscious mind of the man that can disrupt Narcis’ connection with it (This varies from subject to subject, as one man could secretly despise his children where another man loves them). The human mind is one of the few cases where the subconscious mind continues experiencing what Narcis’ mind is doing while the conscious mind is dormant. Persons, places, or things that relate to the subconscious mind of the suppressed person can cause the mind to wake up and eject Narcis in certain cases. If it weren’t for this, the human mind would be the easiest for Narcis’ mind to control, as it operates the same way as he does. 

Narcis has no control over this ability. If the brain of whatever body Narcis is in dies before his mind is able to eject (ie: he is unexpectedly shot in the head from behind) an impression of the suppressed conscience is made on Narcis’ mind. This can lead to hallucinations, psychotic fits, and a myriad of other negative effects. The more complex the brain, the more extreme the side effects. [/hider]