Use Havels Greatshields Stoneskin buff or Great Magic Barrier depending on the situation
Stone Greatswords gravity status= Anti fast rolls. Take advantage of the 10 seconds this status lasts and backstab your opponent who cannot run or roll; you can also use Gravelord Greatsword Dance, your opponent is unlikely to avoid the miracle (use it twice if you can). If you have low HP you can just distance from your opponent and take an Estus Flask/Humanity.
Use of Avelyn is situational.
Note: Im new at PvP so this build may be garbage, post a comment if you find any flaw or if you think there is something that can be improved.
