Heroes Who Did The Least Damage

[Forsaken Lover]

Final Fantasy has a long, proud tradition of protagonists aiding the villlains and/or doing great harm.

Cecil - Helped collect multiple crystals for Golbez, wiped out the Summoner Villge
Cloud - ...where to even start? I guess we'll just finish with the fact he gave the Black Materia to Sephiroth.
Squall - Took Rinoa into space thus freeing Adel
Zidane - Broke the seal to Terra and defeated Garland, allowing Kuja to hijack the Invincible and gain Trance

All these I know of and there might very well be more in FFV, VI, X or XII.

So, what other ways have our intrepid heroes screwed everyone?

And who takes the award for doing the most damage?

[Sephiroth]

Bartz - destroyed the seals for the Rift which looked like monsters because of X-Death's spell
Terra - let the heroes and herself get fooled by the Empire to open Esperville and unchain the continent in the end
Final Fantasy X characters - killed Seymour and made him stronger and easier for him to get as far as he came, Nooj, Gippel, Baralai, Paine, et cetera freed Shuyin from the Sealed Cave
Vaan/Ashe - destroyed the Sun Cryst to help Vayne and Venat by making the Undying Ones go away
Lightning, Serah, Noel, et cetera - did as Bathandelus wanted in the end, killed Etro by defeating Caius, no spoilers for Lightning Returns

[Jinx]

Edward in FFIV!