Hubris
The news of a few odd events had reached Eren's ears when he was heading to the city of Osan from the city of Laurel. This was after settling his affairs with Agatha.
According to the city's message board at the entrance, travellers should avoid the regular route toward the city of Osan. There were signs of a mana beast horde attacking passersby under the leadership of an Ace rank one.
There was also news that the city of Osan might be put into lockdown for a couple of days for some security reasons. As a result, the travellers were advised to make plans accordingly- either don't go to the city of Osan or make haste and get there before the lockdown begins.
Eren pondered a bit and chose the latter option. His time in the Lionheart duchy was short after all. He had to make another batch of potions for his personal use before his departure to the Nightshade duchy. He could use the lockdown days to make potions and make out with Nina some more if she is home.