According to the search results, Simon Manus is weak to acid. In the game Lies of P, Simon Manus is a boss that players must defeat. He is highly susceptible to "overheating" and "decay" elemental damage, which can be dealt with weapons like the poison-tipped spear or the Salamander Dagger. However, in the second phase of the fight, Simon Manus becomes much more challenging, using homing disruption rays and an AOE "god-hand" ability that can nuke half of the entire boss arena. To defeat Simon Manus, players must be well-versed in the games combat system and blocking, and they should use strategies like parrying or blocking most of his attacks, except for the unblockable fury attacks. In addition to acid, players can also use heavy weapons to stagger Simon Manus in the first phase of the fight.