User blog comment:CNBA3/Future Filler Arcs (WARNING: ANIME WATCHERS, MANGA SPOILERS!!!)/@comment-7418318-20140628002403/@comment-5303512-20140628012102

1. The way how they would stay in the current time is that they did not traditionally pasted through the Eclipse Gate, rather it would be a big ripple in time and space that caused them to be transported here and thus would not be bound to the Eclipse Gate.

2. They would have attempted to destroy them 400 years ago but would fail because of Igneel devastating them. And when the ripple transported them to the present time, they still attempted to caring out their goal.

3. Their goal would be to bring the catastrophe by destroying the seals.

4. Their reason for it is that they see this world is corrupted, humans killing each other, war, famine, discrimination. They believe the world cannot be fixed, so the world must start over. They called their mission "New Dawn".