Jonason, Slomski and Partyka's 2012 study found that the three dark triad traits map onto distinct influence styles rather than to a general unpleasantness.
Machiavellianism was associated with hard tactics — threats, manipulation, coalition-building against a target. Narcissism was associated with soft, appearance-based tactics: charm, self-promotion, offers. Psychopathy was associated with coercion and with the harder tactics generally.
The useful implication is that the influence style is itself diagnostic, and it can be observed without any claim about anyone's psychology.
The detection principle is the one in this chapter's title: charm up, pressure down.
The characteristic signature of a workplace operator is a large behavioral difference across a power gradient. To superiors and to anyone with the ability to affect their standing: attentive, credit-sharing, warm, impressively competent. To subordinates and to anyone without: dismissive, credit-taking, inconsistent, and applying costs.
Targets consistently misread this as a personality clash — as something about the relationship between two people — because they have no access to the other half of the gradient and because their own account contradicts what everyone senior observes.
So the protocol is comparison across levels, and it requires other people.
Ask a peer at your level whether they experience the same. Ask someone junior. Note whether accounts of the person differ systematically by rank rather than randomly by individual. A difficult colleague produces mixed reports at every level; an operator produces a clean gradient.
Two further signals are worth watching for. Credit and blame flowing in opposite directions along the same gradient. And information asymmetry maintained deliberately — meetings you learn about afterwards, decisions attributed to a consensus you were not part of.
The counter-response is documentary and collective, in that order, because neither works alone.
Written trails: confirm verbal instructions by email, summarize meetings, and date everything. This is not paranoia; it is the only defense against an account of events being revised later, which is chapter 330.
Coalitions: an operator's advantage is that each target experiences it in isolation. Two people with consistent independent accounts change what any process can conclude, and three change it completely.
Then escalation, with the record, to whichever function is responsible.
The order matters. Escalating without documentation and without a second account puts you in exactly the position chapter 313 describes, and the response you will receive is DARVO.
This counters Law 20.