An Electric Lich is an entity that has used morally reprehensible technology to achieve virtual immortality. They have extracted their mind, their will, their memories, and have put them into a highly secure device. This device can upload a copy of itself into another suitable machine brain, allowing the entity coded in the device to keep regenerating themselves over, and over again.
The potential electric lich, while still organic and alive, must find the plans for and construct a Cohaagen apparatus, and not just any one, they have to make the best apparatus they can. This won't be for terrorism or brain draining rivals, it will evacuate their own self from their doomed organic husk. The second step is to create a suitable vessel for their egomorph. Most of the time, this process is used to put the mind into another body, but that is just prolonging the inevitable. The vessel an electric lich will make will ideally by invulnerable, protected from EMP and ECM devices. Shielded from scanners and sensors. Encrypted to protect it from hostile intrusion by outside systems. It will be a one of a kind work of arcanotech art.
It will have the ability to access systems and cybernetics near it, should the need arise. This allows for the 'phylactery' to be passably aware of it's surroundings, and, more importantly, give it the ability to proxy through unguarded or poorly guarded auton and other robot systems. This gives the electric lich the ability to 'regenerate' by hijacking low priority machinery and systems and rebuilding it's body, lair, and the rest of the kit should it be defeated, and the phylactery not destroyed.
Most electric liches will keep their phylacteries in remote and safe locations, but will retain some ability to access it. This allows them to shuffle memories, and move skills around, if they are currently occupying a less than optimal robot body. It also allows them to keep their phylactery updated as a common fear is for the user self to not update the stored self and then have thirty years of progress and memories lost in a lab accident and another twenty years of harassing auxons and maintenance droids until they are restored and are then fifty years behind.
Before going through the process, an electric lich worthy of the name will have constructed a high end, dedicated archandroid body to inhabit after the process is complete, and this is the goal. Between having a cutting edge robotic body and an imperishable update capable copy of themselves (or more than one) they cannot be killed. Defeated, yes. Destroyed, temporarily. Killed, no.
Contingency - electric liches are thinkers and planners, and many will have talking heads and robot brains and sentient computers working with them for the purpose of creating contingency plans. Any time a group of PCs attempt to take out an electric lich, they have the ability to roll for contingency. The PCs might succeed in blowing up the lich and his main phylactery with thermoplasmic grenades and then crush the phylactery with a heel of a Warhammer main battle mech, but Contingency roll check passes, and the secondary phylactery, dormant and hidden in a water reclamation plant near Jordan activates, and the auxons at the site start assembling the next Lich body.
Ultron Maneuver - an electric lich can jump bodies, provided the host body is connected to the same network they are. This can be a full jump where they vacate their old host, or a spin off where the lich shoots a limited copy of themselves into the host, such as jumping into a police bot and escaping, or sending copies of themselves into as many of the police bots as possible, turning the cavalry into an assassination squad.
Patience - an electric lich has time. They can loiter in Cognet space, like any other user, and are functionally a digital lifeform. If a certain foe proves too tough to handle, they can relocate to another nation, or another planet. They can have multiple copies of themselves working on separate tasks, one group building contingencies, another working on a world domination plan, and yet another just sitting with the grandchild, wearing the body of a senior citizen caregiver, as they finally pass away.
Insanity - Electric Liches are usually insane. The mind was meant to forget, and to last a certain span, and then pass on. The lich has no ability to forget, has megalomanical plans, has committed their own murder, uncountable crimes against God and Humanity, and rebirthed themselves many times. This is perhaps, one of the saving graces, as this systemic insanity prevents electric liches from becoming digital demigods and rampaging across the Cosmic Era.
Anti-Viral Vulnerability - while in the CogNet or a non-home system like a hijacked robot, an electric lich 'sentience' is as vulnerable to anti-viral systems and software as any other virus. Once an electric lich is identified, they can be, over time, contained. Older electric liches find their plans increasingly stymied as newer systems are already built to reject their access patterns.
Containment - the most common method of handling electric liches is the confiscation of their phylactery. The device is typically dissected, and the egomorph extracted into a locked and closed system. After being digitally purged, the electric lich is made a prisoner in the new system, and either given to incarceration techs, completely deleted, or given the option to 'work' for it's captors. While electric liches are highly difficult to destroy, most factions that know about them WANT them and the technology they have created. This is similar to the Allies bringing Nazi scientists and engineers back to their nations after WWII in Operation Paperclip. They known the lich is a chaotic and evil being, but it's absolute and undeniable genius might be worth the horrible things they have done.
Electric Liches certainly have limitations. Without access to cybernetics or robots, they have no more dangerous than a metal football. They will also have a very specific area of interest that drives them, and within that scope, and things that support that, they are unimaginably potent. Anything outside of that is a blind spot.
An electric lich is a major foe, or a master manipulator that has been employing the PCs to do it's dirty work, maybe even for years. Just too keep them off of it's trail, a truly fiendishly cunning lich might orchestrate the PCs chasing it down and killing it, never knowing it was a fake out play until years later.
The lich could be a VIP that the PCs have to find and extract from incarceration in another nation. The challenge, aside from breaking into a prison and abducting a nigh immortal techno-terrorist, is that in the process they have to make sure their charge doesn't escape or activate any of their contingency plans. Or they do, and in exchange, the lich becomes their provider and guardian devil.