Is it possible to change banner buffs (eg.. war banner, 'the immortulz', mark of khorne, etc..)

[Dannstark]

Title

I can't find anything in DB that changes their buffs

[Millimidget]

The table you're looking for is effect_bundles_to_effect_junctions.

One easy way to have started would be to use DaVE's global search function. For example, a search for Mark of Khorne turns up only five results from four records across four tables. Repeating the search using field input from those records would have eventually led you to the table I mentioned above.

From the looks of it, banners are a special case; this is apparent in the ancillaries table, where there's an entire column devoted to flagging which ancillaries are banners. And in effect_bundles_to_effect_junctions you can see that they have a unique scope. In fact, when you do getting to modding the table, it would be helpful to sort by the scope column, as that will sort all banner effects together.