"I'm afraid I can only regretfully tell you, Professor Schiller, that I really have no idea how to cultivate edible plants on a large scale. Everything I grow is edible, but the problem is that probably no one would risk getting punched into a fracture just to harvest them. Even for Gotham farmers, that's a little too exciting."
"Then what about the guardian plants you mentioned before, Professor Pamela?"
"I do have some ideas about that." Pamela nodded and said, "Bruce and I both think there's something wrong with Gotham's rainwater, so we found a way to collect some and use it to water plants for comparison experiments."
"After several rounds of experiments, we found a suitable ratio. Watering plants with it can cause some Madness factor to develop within them, but it isn't the bad kind of madness."
"In mystical circles, this kind of madness is more like 'exuberant vitality.' You can think of it as a plant stimulant. Plants watered by Gotham rain for long periods all retain traces of it."
"And if I use the power of The Green to stimulate plants containing this Madness factor, they can possess considerable offensive power and serve as guards."
"But I heard that some of the plants you cultivated would attack people uncontrollably?"
"That is unavoidable. Anything in this world becomes highly aggressive after going mad. But after several iterations, the latest Tree Sentinel I created can already understand basic commands."
"But it isn't perfect, is it?"
"Of course not. There is still plenty of room for improvement. They can only understand very simple commands, such as staying somewhere and waiting, attacking someone, or attacking people under certain circumstances."
"The tree demon Sergei, whom Night Master Jim borrowed from you to carry out guard duty, is the same way, correct?"