The function takes a string input and modifies the last character of the string. For a lowercase alphabetical character, it replaces the last character with the next character in the alphabet. If the last character is 'z', it wraps around and replaces it with 'a'. For uppercase alphabetical characters, it replaces the last character with the next uppercase character, wrapping from 'Z' to 'A'. It doesn't modify numeric and special characters.

[CODE]:
```python
def modify_last_character(input_string):
    last_char = input_string[-1]
    if last_char.isalpha():
        if last_char == 'z':
            new_char = 'a'
        elif last_char == 'Z':
            new_char = 'A'
        else:
            new_char = chr(ord(last_char) + 1)
    else:
        new_char = last_char

    output_string = input_string[:-1] + new_char
    return output_string
```
