Harper’s optimal weapon is her exclusive weapon, Mischievous, which enhances the team's dark attribute damage upon activating her ultimate.

In cases where the exclusive weapon is not available, the Ancient Grimoire serves as an alternative, offering an increase in power gauge acquisition. This is particularly useful given Harper's extended presence on the battlefield.

Top Recommendation: Exclusive Weapon Mischievous

• In addition to boost in HP, it increases team dark attribute damage when the ultimate is used.
• As the advancement level increases, the damage boost rises incrementally from a base of 4% by 1% per level. At 5th advancement, the damage boost jumps from 8% to 12%.
• Harper herself has strong damage output, and the dark attribute composition of a main DPS, sub-DPS, and breaker (Harper) makes the damage boost buffs highly efficient.

Second Recommendation: Ancient Grimoire

• A staff can be used, but the Ancient Grimoire is better suited due to Harper's longer on-field time as a breaker​.