The Final Stretch

The purpose of the Fifth Syllable of Eni was not to attack nor defend, which is why Kieran chose not to conjure it to deal with the incoming attacks. 

The syllable's purpose was to act as an equalizer, which meant it would regulate the inconsistencies within any structure it was applied upon.

Once Kieran understood this, he realized that the Archaic Syllabary of Eni possessed a certain affinity and some of its components were more universal than others. 

This realization fueled Kieran's next actions.

'It's not creating a Mystic Cipher. What I'm doing is more so using a newly learned power to correct a preexisting one,' Kieran thought.

A moment later, he began conjuring the Fourth Syllable of Eni while simultaneously employing the principles of the Fifth Syllable of Eni. 

The result was Kieran's creation gaining an overall sturdier presence.