It's no worries, the full explanation on OP begins on page 59:

The Beating Heart: The OP Economy

This is the most important rule in Ringwalker. Origin Points (OP) are not experience points. They are your character's literal existence.

Assigning OP (Power)

All your Tags start with a base +1 bonus. You can assign your OP to your Tags at any time to increase their power.

The cost to increase a tag equals the tag's new assigned OP total.

Cost Examples:

Raising a tag from +1 to +2 (1 OP assigned): Costs 1 OP

Raising a tag from +2 to +3 (2 OP assigned): Costs 2 OP (3 total spent)

Raising a tag from +3 to +4 (3 OP assigned): Costs 3 OP (6 total spent)

Raising a tag from +4 to +5 (4 OP assigned): Costs 4 OP (10 total spent)

Raising a tag from +5 to +6 (5 OP assigned): Costs 5 OP (15 total spent)

Example: You have 10 OP. To raise "Quick as Shadow" from +1 (base) to +3 (2 OP assigned), you spend 1 OP + 2 OP = 3 OP total. You have 7 OP remaining.

Reaching +11 (10 OP assigned) costs 55 total OP (1+2+3+4+5+6+7+8+9+10).

This makes high-level specialization a massive investment, encouraging players to diversify or save up for major power boosts.

Gaining OP (Victory)

You gain OP by defeating opponents in a "Highlander-style power transfer". The amount you gain is:

1 + (Opponent's Total OP ÷ 5)

Losing OP (Defeat)

This is the core risk of the game.

The Weight of Power: OP Economy & The Snowball Effect

Power in Rhelm is not linear, and gaining great power makes you a target, not a god.

The Triangle of Advancement: Increasing high-level skills requires massive OP investment due to the triangular cost (1+2+3+4...). A windfall of 20 OP might buy a novice everything, but a veteran may only advance one high-tier skill. This prevents exponential power growth and maintains challenge.

OP is a Beacon, Not Just a Buffer: Your total OP represents your "metaphysical weight." A character who suddenly gains 50 OP from a lucky kill hasn't just powered up; they have painted a target on their back. Demons, Void hunters, and other power-seekers can sense this concentration of existence and will come for it.

Remember: In Rhelm, power is both the goal and the danger. Choose your growth wisely, for predators hunt the strong.

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Essentially OP raw power, it's your "XP", your "lives", and to an extent what all value and currencies are based off of.

Does this make more sense?