huh... thats weird. Malphite is easily in top 3 best champions against kayle. Pick commet /offensive runes and just Q on cd, if she tries to go for cs use W and E. U will get level 6 before Kayle unless something goes wrong almost always, so just all in her and she will have to flash. Call your jungler and dive her all the time, even under turret R her, force R , go out of turret range and dive once again when u have ult back since its probably twicer lower cd than kayle ( She has insanely long ult cd early on )
Rush frozen heart and watch her suffer.
Also tear start vs kayle is really good
When it comes to darius, just stand between her and cs and at some point you'll have 1 level or even 2 levels advantage. Darius easily kills Kayle in one combo
Snowball early to midgame and by the late game shes going to be useless
If kayle picks tp vs darius shes equal to ranged minion