The Book of Darkness and The Wolkenritter have caused a lot of problems for the Heroes of the series. Excluding the planets destroyed previously by the book, and the death of Chrono's father, the Wolkenritter attacked and drained the Linker Cores of several people, hurt the people who tried to defend their victims, caused untold amounts of property damage, antagonized multiple groups of Super Heroes and, willing or not, were responsible for the deaths of Archer and Berserker. In spite of all this, when the main cast finds out about Reinforce intending to sacrifice herself the general reaction was along the lines of: "Are you nuts? That's a stupid idea. Come on, sit over here so we can come up with a real answer".
Several centuries after Nanoha died, her ring, which had gained sentience and become a Green Lantern itself, dedicated its existence to fight the good fight and keep her memory alive.