The phrase "main catalyst" refers to something or someone that is the main or primary factor responsible for causing a change or triggering an event. It can be seen as the key element that starts or accelerates a process. Full definition
Tactically the man's incompetent and before you start talking about his Premier League titles remember, or maybe you won't, he inherited George Graham's defence and also had the privileged to have Dennis Bergkamp in his side who was main catalyst behind all his early success. (justarsenal.com)
As usual the former Manchester City man was his side's main catalyst in attack and at the heart of everything good. (italianfootballdaily.com)
Security is Microsoft's main catalyst in pushing Edge to its users in Windows 10. (windowslatest.com)