The number of keys to meet duelists is based on their level. Players have to use the more number of keys as the duelist's level is higher.
Required Key QTY (Neutral)
Required Key QTY (Color)
How to Get
Players can obtain gate keys as rewards for winning duels. Having duels against standard duelists will be the main way to collect the items. Standard duelists take 30 minutes to reappear after defeated, and players can get them to show up immediately by using the Duel Orb.
Gate keys are also rewards for completing weekly and stage missions.
Players can gain the items by defeating other players, although they will be stronger than standard duelists.
You can also convert no-colored gate key into the colored one by meeting Card Trader. However this way is undesirable relative to other ways noted above, since so many neutral gate keys are required to have a duel against legend duelists.
You can hold 9999, and after that they put the gate keys in the gift box for you. You have a month to claim them. So basically you wont lose gate keys unless you max them out, and keep farming only SD for a full month.
Personally, I saved them in the gift box until i got to stage 27, and then started using gate keys to farm LD 40. Don't bother farming LD30 and under.
I swear, this game no longer gives me green keys anymore because the game knows I'm building a weevil deck. I'm a customer, I want my green keys to farm Weevil!
What world are you living in to where you only need 5 keys? You are clearly not playing the same game
At what stage does Yami Yugi become available in gate? Currently I'm stage 25 and have a mission to defeat him for times to advance to 26. I'm gold 1 in rank and PvP will literally take forever to complete the mission..