Does Elidibus actually think he can defeat the WoL?

[Scintilla]

The other thing also is that the Warriors of Light have never struck anyone down without due cause. The ones on the First refused to kill the Shadowkeeper as did the main hero when she asked to be struck down, and when they came to the Source as the Warriors of Darkness the hero didn't kill them.

Although Ardbert and his comrades spared Cylva, instead turning their attention to the Ascians who manipulated her, there's several cases in which they could be argued to have (or at least attempted to) struck people down without due cause. Upon meeting the Scions in the Source they launched a completely unprovoked attack. Later, despite Thancred and Alisaie's attempts to flee, they continued to pursue them, almost killing Alisaie in the process. Ardbert also attempted to attack Minfillia out of anger around the lack of action to tackle the flood of light on the First. They may have believed their actions to have been for good cause, but then the same could be said for many other groups we have opposed: Beast Tribes, Ascians etc.

This also brings into play the whole grey-area of perspective. How many creatures has our WoL struck down for the sake of training? What of the members of the various Beast Tribes we've killed on our mission to defeat primals? Whilst some of them may have posed a threat and been willing to fight to the death, how many of them could have been more alike to Ga Bu but just happened to be in the wrong place at the wrong time? Realistically, we don't know. Our actions are unmistakably good from the perspective of ourselves and the Eorzean Alliance but much less so from other viewpoints.

By himself not by a long shot,he needed Zenos body to almost manage that~
but he can manipulate others soo

Elidibus would probably do whatever it took to avoid direct combat with us unless we were at a disadvantage since he is only an emissary and the last of his kind, if even Emet's full force against us still resulted in his defeat then for Elidibus to go head to head with us would be suicide.

Given his role, it could be feasible that Elidibus' strengths may not lay in battle, though it may be too early to discount him yet. We can't compare our previous duels with Elidibus with our battle against Emet-Selch. Once it became apparent that the odds were stacking against him, Emet quickly discarded the limits of his vessel and went all out to defeat the WoL in his true form. So far, we've only ever battled Elidibus whilst he's in the confines of a vessel (albeit a highly able one).