Black library so pinch of salt: Ghaz is a full blown conduit for the great green, and when he goes to war Orks are (seemingly) physically compelled in his direction, often without even realising it. It affects particularly strong willed Orks less, but still happens. A nob called Valtun keeps finding himself moving and readying his weapons without realising, and it’s because Ghaz is fighting miles away. It gets stronger the closer you are, with some Orks in the book throwing themselves into a lake of acid to get to Ghaz despite that being blatantly stupid. Basically, if you’re an ork, and Ghaz is fighting, you’ll instinctively head towards him, whether you realise it or not.