Era
Middle Ages
At first, the Zenan Bridge is destroyed, but it is repaired by the time you return from the End of Time. Speak to the knights there, then get their rations from Guardia Castle. Upon your return, agree to help them. I wouldn't recommend bringing Robo, since you'll need magic here and his Laser Spin is not very effective. You'll fight a number of battles against undead and Ozzie. You can defeat the Deceased with magic, but having everyone attack Ozzie will cause the battle to end just as easily.
Zombor's top half will negate one Character's entire MP total if it dies first, which can be annoying since magic is your most effective means of attack. The Bottom Part is vulnerable to Lightning and Fire, so have Crono and Lucca pound away while Marle heals. The Upper Part is easier to hurt with Physical attacks, and both ✩Ice and Antipode are effective.
Zombor's top half will negate one Character's entire MP total if it dies first, which can be annoying since magic is your most effective means of attack. The Bottom Part is vulnerable to Lightning and Fire, so have Crono and Lucca pound away while Marle heals. The Upper Part is easier to hurt with Physical attacks, and both ✩Ice and Antipode are effective.