For Threat of Pokari, this involves talking to Ziola (The East Market) to accept the quest and then retrieving an item called Dangerous Items. After accepting the quest from Ziola, you will need to go to where Woodsman Roki (The West Market) is. Around him you will see various chests called Dangerous Items when you hover your mouse over it. As there are 5 such chests around Woodsman Roki, you will/might have to check and see which are the ones you can retrieve by hovering your mouse over them.

Once done, go back to Ziola (The East Market) to submit the quest. Sometimes, if you're lucky you might get this item called Anonymous Letter.

If you don't, do not fret though. As long as you have alt(s) that are Lv60 and above, those alt(s) are eligible to pick up the quest itself. Because, this Anonymous Letter can actually be traded between players or even mailed from your alt to your main. But how do you know if you have this letter? Simple! If you're lucky, the right side of your game client screen will let you know, or alternatively, you can check your bag since this Anonymous Letter will automatically go into your bag. At this stage, take note that if you talk to Ziola and accidentally click on the 4th part of Threat of Pokari, the Anonymous Letter quest will automatically be logged onto your alt(s) quest log. And you wouldn't want that to happen if you know you need the extra EXP to level up.