Last Chaos Guide to Upgrade Item
Playing Last Chaos, for item that is up to level 145 (buy Lastchaos Gold), such as +10 or +11, that you can use a CSS (guaranteed to add one plus with no chance of breakage and no chance of downgrade). Also can use an HS, but make sure you use it with a RoP II, to insure against breakage, be aware that the item can be downgraded in this manner. You can attempt to upgrade it with an HS and no RoP II during an Upgrade Probability Increase Event for which see below.
While for item that is +12, you have a choice, depending on how high you want to plus the item which is most items below level 70 or so do not actually need to be higher than +13 for PvE purposes), and whether or not an ES has previously been used on it. You can either use an ES (guaranteed upgrade of +1, with no chance of breakage or downgrade) on it to make it +13 and then stop trying to upgrade the item, or you can use an HS with an RoP II to attempt to get it to +13. This method, however, although it will prevent breakage of the item, may still result in a downgrade back to +10.
If you intend to try to get the item to +15, it is recommended that you use an HS with an RoP II to attempt to get the item f Aion +12 to +13, or that you make your attempt with an HS and no RoP II during an Upgrade Probability Increase Event, for which see below, because an ES can only be used once on any item.