Mu En had originally kept the Dragon Core to nurture a junior who could shoulder Shrek's burdens after him.
If he could not find a suitable successor, Mu En had even planned to pass the Dragon Core to Bei Bei before he died.
But now, Shrek had no suitable successor, and Bei Bei was too indolent to amount to much-mud that could not be plastered onto a wall. Mu En could only use this treasure as one of his bargaining chips.
He understood perfectly well that resources and money alone might not be enough to persuade Wang Xian'er.
If a Limit Douluo lived a few more years, what resources could she not gather?
Unless he had a treasure tempting enough to move Wang Xian'er, she was very likely to refuse.
The Dragon Core was precisely the treasure Mu En had offered to make it difficult for Wang Xian'er to refuse.
He could tell that the relationship between Wang Xian'er and Su Yuan was far from ordinary. And since Su Yuan had a dragon-type martial soul, the Dragon Core would be immensely useful to him. As long as Mu En's guess was correct, Wang Xian'er would certainly agree to this deal for Su Yuan and the Dragon Core.
Everything else was an extra, but an indispensable extra all the same.
For Shrek's sake, Mu En had racked his brains and considered every angle.
"Now, all that remains is to wait for Wang Xian'er to bring Su Yuan back to Shrek when the term begins..."
"Xiao Yuan, the Nether Duke has given us an answer regarding that Zhu Family descendant you encountered when Shrek's term began."
On the way back to Shrek, Wang Xian'er also briefly mentioned the matter of that swine-fever fellow to Su Yuan.
"Oh? What did the Nether