the quanta drain is the main mechanic. the relic is a thematic addition to the denial mechanic.
I disagree with your analysis completely.
A devourer does not require another card to absorb quanta. period. it can be played the first turn and start to deny quanta before the opponent plays a single card.
This card requires 2 other cards to drain quanta. A kill card (in element that would be plague, virus or aflatoxin). and an opponent creature.
Lets take your average creature, for arguments sake lets take it to be the elite mummy (5|3) for 3
.
best case scenario for this charon's bribe:
Turn 1: pay 4
for charon's bribe and a virus.
Turn 2: infect elite mummy with virus
Turn 5: mummy dies and opponent is forced to pay 3
.
equivalent with devourer:
pay 2
, wait 5 turns to absorb 5 quanta and gain 5
. No other cards involved, denial begins immediately, Quite possible you have prevented the opponent from playing needed cards.
Any faster combo with charon's bribe requires duo elements. Mass CC means nothing if the opponent has not played a mass number of creatures. (malignant cells dont cost anything so you cannot force the opponent to pay for their death) I in no way find this to be overpowered. Having this drain quanta from you makes about as much sense as having devoures drain from their owners.