Usage
{{Character Tabs|character name}}
or for pages with different display names:
{{Character Tabs|Λ-No.11-|Lambda-11}}
Testing
1 Character
2 Character
3 BBTAG
4 No subpages
5 6
Notes
Uses the SubPageList extension, which supposedly should work as intended. However, template parsing fails and showpage=yes might not be working as intended (instead of being appended to the list as a list item ("li" element), it is being appended as a separate paragraph ("p" element), which complicates styliing).
For now tabs will only show the list of subpages.