I love Gwyns theme because it just sets the mood perfectly. Its not loud & crazy its just a soft piano. Which kind of catches you off guard because the first time youre about to face him you think youre guna have an epic fight filled with explosions & toppling buildings but no its the exact opposite. You finally meet this king whom during the entire game is built up to be this amazing powerful lord but when you meet him he's actually just a deteriorating old man who has lost everything. A shell of his former self. So this song plays this entire scene perfectly making it my favorite. If not this one then probably Artorias's theme or the bell gargoyles theme. Edit: whoops you said Dark souls 2 theme. Um probably would be the skeleton lords theme or again the bell gargoyles theme.