Core didn't initially see an option that would let him use the spear and the club which were locked behind a feature, but maybe once he opened the layout interface he'd see an option.

  Core's very happy to get an additional defender slot, and he made that his first priority to select a new defender to bolster his defenses. He currently had six different types of defenders of which three already walked his dungeon. The three he already had were discarded as choices, since he wanted a large variety of defenders to tackle all kinds of threats that might wander into his dungeon. This left him with a choice between the rat, the pudling, and the snake.

  He almost instantly discarded the rat defender, while the mana cost was low, so were the statistics. Core needed strong defenders now, maybe they could become better when they leveled up but that took a long time. His other creatures were still level one after he already became a level three.

  He compared the pudling and the snake to each other. The pudling had the aquatic passive ability but that was disabled for the skeletal version. It also shared similar statistics with the goblin. Once he had water and living pudlings they'd be a solid choice. The snake was his latest addition and while a bit expensive mana wise it had good statistics, it also possessed two abilities.

  Core liked ambushes and traps, so the passive effect of detection reduction that the snake possessed seemed a perfect fit for him. Core could already imagine unaware invaders being ambushed from behind by the stealthy snake. Its skeletal form wrapping around the unsuspecting victim and leaving it helpless to defend itself. Core opened his Defender creator tool, selected the snake, and confirmed the selection. Mana was drained from his reserves and the snake formed out of rainbow-colored particles in the dead-end of his short tunnel. The snake coiled up in the dark tunnel and awaited its master's commands.

  With the matter taken care of Core already felt a bit saver with a strong addition to his defense force. He pulled up the previous level up notification and looked it over ones more. In addition to a new trap slot, he also gained a whole new type of trap, the wall and ground spikes. He opened up his trap menu to get a closer look at his new trap.

  Very similar to his pitfall trap in execution of skewering the target that activated the trap, but he could link multiple sections giving the trap an increased range. The act of linking the traps would also increase the cost of each section by 5 mana and the time for the trap te rearm would be increased by 25% for each linked section. Core didn't mind that at all. He already assumed invaders wouldn't fall for the same trap twice. His tunnel was also one route, so they'd never get back to activate the same trap again. He'd have to take some time, later on, to think about how to best utilize his new trap.

  Core pulled up the level up notification one last time to check up on his new feature the Dungeon layout accessory assets. He opened up his Dungeon layout tool and activated the new feature.

  Core let this new information sink in for a moment before he made his choice. Variety and Utility sounded pretty vague terms, he'd likely learn more by choosing < Yes >, but he had questions for System first.

  "Hey System, what are floors and theme's?"

  Now that was good to hear, while he still had a lot of room to expand his dungeon on this floor, it was good to know he could get even bigger with better defenses in the future. For now, he's only level 3 so making it all the way to level 10 was still a far way of for him. Core then he selected the < Yes > option.

  He instantly regretted his action as a giant overview menu opened up with all the newly unlocked assets.

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  The information overwhelmed Core, and he quickly resized the screen so it would only display one line at the time.

  He already learned about the need for light sources when he'd use living defenders instead of his undead ones. He also remembered the last pudling that ran towards the light, maybe he could use the torches to lure invaders towards the light and into a trap.

  The door looked fascinating as it meant another obstacle for an invader to get through to reach his Core. He'd test it out later since it seemed that he also needed to get the switch at the same time, he also wondered what the difference was between sentient and non-sentient. He made a mental note to ask System about it later on.

  With the water, he now had the solution to his pudling problem on how to activate their passive effect. Being an avid user of traps he assumed the water feature was used to hide the fact that a sudden pool of water was suspicious.

  Core didn't see the rock formation having a practical use, for now, so he ignored it.

  The root growth, while expensive, gave him plenty of options to hide other things like traps, defenders, and passages to switches.

  Core instantly placed a collapsed tunnel before his new snake defender when he read the description. He ordered the snake to move past it and it nimbly complied, its Silent passive made it almost impossible to detect the snake moving past the rocks.

  The twenty-five mana he'd gained from his level up were quickly spend, and he once again found himself pretty low. His mayor project would yet have to wait until he was done utilizing the assets menu to improve the already existing dungeon.

  He spent the next hour trying out all his new assets and learned a few interesting things. While he didn't have the mana to place most of the items if he placed them on his Dungeon layout tool he could see the effect they had on his dungeon in advance. The door and switch would indeed need to be placed together. The door would remain a red color until he also selected a spot for the switch. The water feature could be placed anywhere and so could the collapsed tunnel. The root growth needed three unblocked adjacent squares but could be placed on top of the new wall spikes trap.

  Core also placed the glowing moss, torches, and the brazier onto his layout. The light glow coming off from all of them would show what would, but more importantly what wouldn't be illuminated by the light. It seemed that if he placed the light sources just right he could create dark zones. These dark zones could easily act as ambush spots where his defenders would remain out of view until the last moment. Overall Core was happy with his new feature, he already had a good amount of ideas he could implement to his dungeon and his project, that once again got delayed.

  He spent some mana to periodically place some moss just so the outline of the dungeon was visible. Having a source of light meant that even invaders who lacked vision in darkness of had a light source could find their way deeper inside into the waiting fangs and claws of his defenders.

  With his lack of mana holding him back, Core decided to go watch the rain fall outside his dungeon for a while. This made him wonder if the water feature would have the same relaxing effect as the gently falling rain. Core was clearing up his Dungeon layout tool, saving the possible alterations he had made for a later time, when an all to familiar box popped up.

  Core gave a glance at his dungeon entrance and saw another single pudling had entered. He wondered if the rain made them extra active since four of them entered his dungeon in a short amount of time.

  As the pudling was making its way through the tunnel, Core saved the last of his work and gave the newest invader his full attention. The pudling had light blue scales and the scales that ran from the bridge of its nose to the back of its neck were colored red. Core wondered for a moment if the different scale colors had a meaning for them.

  The pudling either didn't need a glowing sphere or the moss that Core had placed was enough for the invader to find its way forward. He let the invader walk past the caved-in tunnel feature before he commanded the snake to move out and stalk its prey. He thought about just grabbing it right there in the tunnel, but he decided against it. His creatures needed experience and level to get stronger. Instead of having only one of his defenders gain the experience, he would let the spider in on the action.

  The red scales on the pudling certainly didn't improve its perception as it failed to notice the hidden spider and it gained another increase for its passive talent. The snake was quietly stalking the invader ready to strike at its master's command.

  Core commenced spider to pop out of hiding. His plan was not to launch an attack but to scare the pudling. The moment the spider popped out the pudling flinched and stood there looking at the suddenly appeared defender. It was the final mistake the pudling would make. With its full attention on the spider, the snake easily launched the sneak attack, before the pudling could even respond its legs were already bound by the snake as it slithered ever higher onto its victim. Now having to deal with the new threat he hadn't detected before, the spider launched an attack as well.

  The combined attack overpowered the pudling completely. It tried to resist the snake's attack by trying to push it off, but it was of no use. The spider sank its fangs into the now mostly helpless invader. Alternating their attacks the spider and snake made quick work of the invader and its body soon disappeared in rainbow-colored flakes.

  Spoiler: Dungeon map