Lukas wasn't metioned in the first game. I am pretty sure he would sensed a powerful shadowling.
Falstaff said, "He was the only one who could sense them, due to his talents, but even he didn't notice thier presence until it was too late." "Only one" is pretty clear. That mean on one else could sense the shadowlings including Lukas.
Even though he is able to hide his power, don't you think Lukas would have gotten susipious after the first shadowling abductions. I think that he wanted to be safe if shadowling attacked Psy Academy (As shadowlings all use shadow attacks).
I agree with that. At the time, he thought war was the only way to stop the shadowling abductions, so he began to prepare for war four years before the Academy joined the Dissidents.