FFXIV:ARR Zoadiac weapon is upgraded in Oatch 2.45, including Shied, Sword, bow, dual daggers, staff and so on. In order to gain the legendary weapon, your class is required to reach level 50 and have to complete the relic quests, explore dungeons, spend soldiery, craft HQ items, gather desynth materials.
The quests include the main quest and some side story quests; all of them is not hard for players, but you need patience to complete them.