After the red ghost was completely intact, this highly intelligent creature with NO.1 strength, which had defeated NEO in ancient times, was only the last step away from its final form. However, the red ghost did not choose to eat Alu. It was assimilated by Aru, and this assimilation is not like the monster form that Acacia took after eating NEO, but only strengthened Aru's entity. This reminds me of Piccolo and Neru in the Namek chapter in Dragon Ball. Assimilated, Piccolo still retains his own personality. The red ghost's words about following Aru and looking at the further future reminded me of Obito giving the Sharingan to Kakashi, becoming a part of Kakashi, and following Kakashi to look forward to the future.

Reading the comics, Red Ghost was moved by Alu and saw the infinite possibilities in Alu. The reason is that if the red ghost is not eaten by Alu, it will not be able to strengthen Alu's entity. But when Bai Gui took a nap before, Aru's body couldn't bear it. Therefore, in order to put Aru and Acacia on the same front, he could only summon the White Ghost to deal with it. To bring out all the strength of the white ghost, the only way is to strengthen Aru's entity. Therefore, it is natural for the red ghost to be eaten by Aru, unlike Acacia. It only strengthens Aru's entity.

So where will the plot go next? After assimilating with the Red Oni, Aru's capture index should be no less than that of Acacia, and there is also a Blue Oni in his body that is no less than the complete Red Oni, as well as a stronger White Oni. It is conceivable that Alu is stronger than Acacia. So how will Acacia deal with Aru next? There is a sentence that may leave some foreshadowing. In the previous comic Blue Nitro, it was mentioned that Acacia would not be able to bear it if she forcefully swallowed NEO. This sentence reminds me of Uchiha Madara in Naruto. Ban ate the Ten-Tails and became the Six Paths Ban. Unexpectedly, he was later attacked by White Zetsu and succeeded Kaguya. So will Acacia be counterattacked by NEO and turn into a more powerful monster to fight against Alu's white ghost? Personally, I feel that it is still possible that the monster after the backlash may turn into a highly intelligent organism, changing the form of NEO that only purely swallowed it in the past. Of course, it is not ruled out that NEO will fail to attack Acacia, allowing Acacia to further evolve.

No matter which form, I think Acacia and NEO need to be further upgraded. After all, the current physically enhanced Alu, plus the blue ghost and white ghost in the body, if fully exerted, Alu will Cassia and NEO should not be its opponents, and upgrading is an inevitable choice. Next we have to see how DD develops the plot.