Bosses: markers, health bar and summoning

New

• Exceptional monsters now carry clear [BOSS] and [EVENT] markers in their own colours — you can tell at a glance what you are taking on. The same markers show up in the battle list.
• When you come close to a living boss, a large health bar with its name appears at the top of the screen. It disappears when the boss dies or when you walk away.
• Some monsters can now be summoned. Every tenth Slime you kill calls forth a Devil Slime on the exact spot of that last kill — and while it lives, further kills will not summon another.