、。
To Tom, Mary is just one of the profit-promising plunder gurus.
Literal
Tom [by-によって], Mary [topic-は] profit [object-を] promise plunder [possessive-の] guru [possessive-の] one [only-しかありません].
An unusually heavy phrasing: 利益を約束する略奪の尊師 ('a plundering guru who promises profit') stacks dense modifiers in front of 尊師, an honorific term for a religious leader (now associated with the Aum cult era). しかありません (only / nothing but) tied with the partial-negation flavor lands as 'just one of the…' — the によって here marks Tom's perspective. Stilted but grammatically grounded.