Of course, even though invincibility was an extremely powerful skill, it came with many costs.
First, the skill seemed to use life to work. After the effect ended, the once-young guard priest had aged to middle-age. According to Galadra, this side effect was probably permanent. Almost all enemy special powers they'd seen had this kind of limit, and some side effects were even more extreme.
In Nicola's memory, her opponent couldn't move at all while invincible, but this Bishop could slowly move forward. This showed he was clearly stronger!
Though he probably couldn't destroy the laser machines by breaking the walls, getting through the channel was just a matter of time.
"Not good, I must stop him!"
Adrian couldn't stand watching anymore. He grabbed his bow, quickly rushed to the channel.
"Wait! You can't just rush in against enemies with special powers! You need to wait for the right moment to hit their weakness!"
Unlike Adrian's men who usually just followed orders, Nicola couldn't just do nothing when she saw him rush off alone. She knew Adrian knew nothing about these enemies, so she quickly chased after him.
The gray-robed Bishop earlier at least used some unknown trick, destroying the defense system from far away to get past the traps - so he didn't seem completely unbeatable.
But this yellow-robed Bishop's way of getting through was just incredible. Adrian knew how strong the enemy was, but he absolutely couldn't let the enemy reach the shelter on the other side! Though he didn't stop, he asked hopefully, like grabbing onto a lifeline:
"Weakness? Do you know how to break this... this invincibility skill?"
He remembered that Nicola did say she had lots of experience fighting Ancient God Religion.
"Um, direct attacks definitely won't work! We think it's some kind of absolute defense at the natural law level, impossible to break head-on - that's why it's called invincibility..."
Since she obviously couldn't handle Bishop-level enemies with her current power, everything depended on Adrian. Nicola quickly explained what Galadra had figured out about this skill.
Usually people wouldn't know this stuff beforehand. When fighting up close, it's easy to get tricked by the yellow glow and stubbornly attack mindlessly - very dangerous.
Luckily Nicola had learned this the hard way before.
"Even the most incredible power must have a time limit! Just wait patiently until his invincibility runs out. He'll naturally become weak then, and with your strength, you can finish him easily!"
By now they'd reached the end of the laser defense. There was a bend where they could hide where the enemy couldn't see them.
Adrian carefully peeked around the corner. Far down the tunnel, he could see the yellow-robed Bishop with half-closed eyes, slowly walking his way while mumbling prayers.
Every couple steps, a new laser net would appear in front of the Bishop, who'd push through it stubbornly. The super powerful laser beams only stopped him for a moment and didn't really do anything. Adrian turned back and whispered doubtfully:
"I just saw his body has some burn marks from the laser cuts! If that's real, maybe if I time my strongest explosive arrow with the next laser hit, aiming at his wounds, we might break through his defense!"
"Don't do it! That's an illusion to trick you, at least rule-level mind control... anyway, it's way beyond normal magic! You must avoid looking directly at enemies while they're invincible. Remember - invincibility means absolutely no damage! If you see any wounds, they're fake. Our only option is waiting until the effect runs out. He'll be weaker then because of aging!"
From Nicola's experience, that guard priest had led her on step by step, making her think she could actually kill him - that's how she fell for it. Thankfully she was very careful this time and didn't dare look at the yellow-robed Bishop at all. Plus Adrian only glanced quickly, otherwise they both might have fallen for it already!
"How long until the invincibility ends?"
Seeing how "professional" Nicola seemed, Adrian stopped questioning. He probably realized that against such a weird enemy, he had to rely on this expert to get through this crisis.
"About fifteen minutes, but since he's a Bishop, probably longer... at least twenty minutes!"
Nicola seemed unsure about this answer and thought for a while before giving her estimate. Since the yellow-robed Bishop was bald and far away, she couldn't judge by looking, but based on his condition, he probably wouldn't die anytime soon.
"Twenty minutes? At his speed, he'll reach the underground shelter in just over ten minutes!"
Adrian's blood pressure shot up when he heard this. The yellow-robed Bishop wasn't fast, but you could see him steadily moving forward.
Plus they say invincible enemies can still cast spells and attack from far away - he was like a slow-moving but untouchable cannon. Not to mention a Bishop's attacks were too powerful for normal people to handle. If they let him continue, more innocent people would die!
"Isn't there any way to stop him here?"
Protecting the few remaining Parristol people was Adrian's top duty as king. He really didn't want to retreat. Plus another Bishop had probably broken through the underground defenses too - they absolutely couldn't let a second one in.
"What can I do? That's why I told you not to be so optimistic at first. Quick, go evacuate everyone! Avoiding direct contact with the enemy is probably our best option right now. Unless..."
Remembering various strategies they'd figured out after past battles, Nicola added uncertainly: "Unless you can use mind control, like spiritual magic. This invincibility probably only covers physical stuff, might not protect the mind at all - but you're a Battle Qi awakener, you probably don't know magic, right?"
Usually only high-level light mages and angels could use spiritual magic. Nicola definitely hadn't learned it, and she didn't have the magic power for high-level spells anyway. As for Adrian, she didn't think he could use it either, so she hadn't mentioned this option at first.
"Mind control? I don't know magic, but I do know some basic mind control techniques!"
Surprisingly, Adrian stood up right away and pulled out two arrows, holding one arrowhead in each hand. Soon the arrowheads were marked with the words for "confuse" and "illusion".
"I'm not sure whether 'confuse' or 'illusion' works better on enemies, so I'll use both! Or maybe other words would be better?"
"What the hell, so your Battle Qi awakener can do more than just make arrows explode?"
Having fought Adrian many times before and seeing mostly explosive arrows, this was Nicola's first time seeing such an "unusual" technique. Feeling like she'd been deceived, she cursed out loud.
Had that bastard Adrian not used full power against her? He was holding back!
By now the yellow-robed Bishop had almost walked past the last laser-covered area and was very close to them. There was no time to waste. Adrian didn't even look at his target - he just shot both arrows from behind the corner. A second later came two clear "ding" and "tang" sounds.
Anyone could guess that the slow-moving yellow-robed Bishop couldn't possibly dodge these arrows. Of course, he probably wouldn't even try since the arrows couldn't hurt him at all!
In the end, the arrows were just tools to transfer Battle Qi - what might actually work was the special effect on the arrowheads. And special attack effects converted from Battle Qi were theoretically much stronger than low-level magic effects.