Mage Killer build

[CASTLEMIKE]

You can't simply create custom magic items by following the magic item creation guidelines and claim them as RAW-approved items that should be allowed in every campaign.

Think of it this way: custom magic items are not campaign-allowable until DM-approved - instead of your view, which is that any custom magic items that follow the magic item creation guidelines are allowed until the DM disapproves of them.

It just doesn't work like that. DM must approve the item, period.

Think of it this way: Candles of Invocation, Planar Ally Spell scrolls, the various Limited Wish, Miracle and Wish magic items, all exist under RAW but still require the same DM approval just like the magic item creation rules.

Yes it does work like that. The DM must approve everything your PC has in his game, period.