User blog comment:Prince of Erebor/Weakest Nen ability/@comment-4753851-20151017182323/@comment-25414015-20151018045853

Sure his ability has its limitations, and is weaker than the original ability used by the person. This goes for all abilities in the series that allows for one to steal abilities. However, in combat, using the correct ability for the situation is invaluable. His offensive power is great with this ability; you cannot deny how versatile this ability is. Pulling out someone's weakness in battle if you could deduce it(Chrollo is sharp and cunning, so this is his advantage) and using it against them, even in a reduced form makes up for the complex planning it takes in order to get this strength. Chrollo's power is weak if he entered battle on a clean slate, that is when his book has nothing in their, but preparing for a battle ahead would make him deddle, and would make up his usage of one arm and stuff like that. Versatility, careful planning, and growth is how Chrollo's ability holds.