If it was just a normal spell I could even cast it right now, but that wouldn't be enough. To have it cover most of the sky above the city it is going to need to be enhanced. The problem is that I don't have enough mana to cast it and enhance it.

Once again I find myself wishing that I had Lin's mana pool, I could do it myself if I had that much mana. Then again, I really like the idea of her enhancing a spell that I cast for once. However, that means that the spell needs a strong, resilient structure or it will fail.

This is the hardest part for me and something I should have forced myself to learn sooner. The way I normally cast spells is faster and easier, but it also has its drawbacks. As I am designing the structure of the spell, the main mass of the beasts arrives above the city.

The flock, or maybe it's a swarm, covers the sky and blocks out the sun over the city. The very air and the roof I am sitting on are vibrating from all the wings beating. It looks like, if anything, that I underestimated their numbers, by a lot.

The city defenses won't hold up against these kinds of numbers for long. I admit, after seeing that, I take a few shortcuts when it comes to the structure of my spell. Even as I try to speed up the creation of the spell, the first thousand Shrikes descend.

What's odd is that there are only a thousand of them, the rest of the swarm doesn't move. The thousand swoop down and arrows rise from the rooftops to meet them. The Shrikes are obliterated instantly, but the second they are, more dive down.

The first thousand were sacrifices, they used themselves to get the defenders to use the weapons. Now five thousand more Shrikes are diving down to attack before the weapons can be reloaded. Unfortunately, the strategy works perfectly and the second wave of Shrikes reaches the rooftops.

Adventurers on the various rooftops start attacking the Shrikes as they come into range. With a couple of spells Lin eliminates all the Shrikes that were heading for out position. Unfortunately, the forces on the other buildings don't have as much luck.

Only about half the wave of Shrikes actually reach the rooftops, but those that do attack the weapons. As the third wave is attacking the weapons another two waves head down. The first group of a few thousand heads to join in the attack on the roofs.

The second group of about six thousand heads straight down towards street level. Again Lin wipes out the Shrikes heading for our roof with a couple of spells. Then she steps to the edge of the roof to target those that got past her spells.

This is the first time I have seen how she fights on her own and I am impressed. Her spells are accurate and perfectly targeted, she doesn't waste any energy. Any Shrike that comes within her range gets wiped out and she looks damn sexy as she does it.

Now that I see her in action, I feel pretty stupid for trying to protect her all this time. Her casting is fast and smooth, enough that I doubt I would be quick enough to interrupt her. She is doing it all with pure mana, I had no idea that she had gotten so good at using it.

At this point her skill at using pure mana is probably already better than mine. It is definitely an eye opener for me and at the same time it excites me. I wish I could pay more attention and watch longer, but I have my own task to complete.

The other rooftops that don't have someone like Lin are not doing so well. A quick glance around shows a lot of the weapons on the surrounding buildings have been destroyed. It cost the Shrikes a lot of numbers to accomplish, but they can afford the losses.

Even with the waves that have attacked so far, the swarm above doesn't seem to have shrunk. What worries me more than their numbers is the tactics that they are using. The level of intelligence implied by their tactics is a lot higher than I would expect from beasts.

That is, unless they are a hive mind, meaning the more they number the smarter they get. I would love to ask Zachariah or Almort, but talking would break my concentration. As it is, if I wasn't paying attention to what's going on I would probably have finished already.

Even though Lin is capable of defending herself and has the choker to protect her, I can't make myself concentrate. I am too worried that something will happen to her while I am focused on the spell. Even the resurrection ring isn't enough to make me stop worrying about her.

About the best that I can manage is to put ninety percent of my focus on the spell. The other ten percent is on Lin and what the swarm is doing. Mainly because if the entire swarm descends I will have to modify the spell.

At this point I just need another couple of minutes and the spell should be ready to cast. As long as the swarm stays put that long, we should be able to save the city. Luckily, it looks like the swarm itself is going to stay put for now, another wave of five thousand breaks away.

The new wave moves down to replace the losses of the waves attacking the rooftops. I am curious what's going on at street level, but I can't see that from here. I do notice that this new wave completely avoids our rooftop, they are avoiding Lin.

Again, that shows a worrisome level of intelligence, it makes me wonder if a demon is controlling them. Even if the swarm has a hive mind, it shouldn't be this knowledgeable of the city's defenses. Then again, it might know if it remembers other Shrikes attacking the city.

I am certainly no expert on hive minds, but that doesn't seem like something they should be capable of. Honestly, I think I would prefer it if it is a demon controlling them, it would be less disturbing. I would much rather deal with a demon than have intelligent demon beasts to worry about.

Those kinds of thoughts can wait for later, for now I need to focus on the last few pieces of the spell. The shortcuts I have taken worry me a little, but I don't have the time to redo them. I am just going to have to hope that the spell holds up as is and that I didn't make a huge mistake.

"Lin, the spell is ready, are you?"

Lin says "Yeah, go ahead! Should I use all of my mana?"