my.kv

#:kivy 1.7.2

<MyBox>
    orientation: 'vertical'
    size_hint: (0.4, 0.1)
    Label:
        font_size: 32
        color: 1, .97, .83, 1
        halign: root.alignment
        text: root.name
    ProgressBar:
        max: root.max_val
        value: root.current_val

<MyScreen>
    enemy: {'name':'Enemy','max':100, 'current':70}
    char: {'name':'Character','max':100, 'current':40}
    canvas.before:
        Color:
            rgb: 0, 0, 0
        Rectangle:
            size: self.size
    AnchorLayout:
        orientation: 'vertical'
        size: root.size
        AnchorLayout:
            anchor_y: 'top'
            size_hint: 1, None
            height: 75
            MyBox:
                anchor_x: 'left'
                anchor_y: 'top'
                name: root.char['name']
                alignment: 'left'
                current_val: root.char['current']
                max_val: root.char['max']
            MyBox:
                anchor_x: 'right'
                anchor_y: 'top'
                name: root.enemy['name']
                alignment: 'right'
                current_val: root.enemy['current']
                max_val: root.enemy['max']

test.py

import kivy
kivy.require('1.7.2')

from kivy.app import App
from kivy.base import EventLoop
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import *
from kivy.uix.screenmanager import ScreenManager, Screen, WipeTransition

EventLoop.ensure_window()

class MyBox(BoxLayout):
  name = StringProperty('')
  alignment = StringProperty('center')
  current_val = NumericProperty(100)
  max_val = NumericProperty(100)

class MyScreen(Screen):
  enemy = DictProperty(None)
  char = DictProperty(None)

class MyApp(App):
  
  def build(self):
      self.screen_manager = ScreenManager(transition = WipeTransition())
      self.screen_manager.add_widget(MyScreen(name='menu'))
      return self.screen_manager

if __name__ == '__main__':
    MyApp().run()