[.../punches you in the nuts]

[He tried. It worked. But he figured now wasn't the best time to say "Oh I bitchslapped your fiancee and it was pretty easy actually".]

Regardless of what happened there, at Akzeriuth, you Ion were tricked by Van into opening the Sephiroth seal and destroying the Tree that supported Akzeriuth, causing the city to sink into the miasma and be destroyed.